Method of operating and calibrating a group of measuring devices

Abstract

The invention relates to a method of operating a group of devices (1) on an operating site (3) and of calibrating said devices (1), wherein: each device (1) is a measuring device (1) and calibration is run according to a schedule determined on the basis of a calibration time interval (A) determined for each of the devices (1). The method comprises the following steps: during each calibration of each device (1): determining a degree of compliance of the respective device (1) with respect to requirements assigned to this device (1), determining a recommended interval (R) for the next calibration of the respective device (1) on the basis of said degree of compliance and determining a ratio (r) of the recommended interval (R) and the calibration time interval (A(t n‑1 )) currently applied to this device (1); reviewing the calibration time interval (A) on the basis of said ratio (r) and a set of pre-determined ratio ranges (I, II, III) by: performing, for each device (1), a pre-determined procedure for the ratio range (I, II, III) comprising the ratio (r) determined for the respective device (1), and updating the calibration time interval (A(t n‑1 )) applied to the respective device (1) on the basis of at least one of: a rule defined for the respective ratio range (I, II, III) and a rule applicable to the respective device (1); and determining a schedule of calibration times (t n ) providing an arrangement in which the devices (1) should be recalibrated on the basis of the updated calibration time interval (A(t S )) determined for each of the devices (1) and performing the next calibration of the devices (1) according to this schedule of calibration times (t S ).

Description

TECHNICAL FIELD

[0001] The present invention relates to a method of operating a group of one or more devices on an operating site and calibrating the devices, wherein each device is a measuring device and the calibration of the devices is performed according to a schedule determined based on a calibration time interval determined for each of the devices. BACKGROUND

[0002] Measuring devices are used in almost all branches of industry. They are typically used for measuring and / or monitoring a measured variable, such as for example a physical quantity related to an ongoing production process or a property of a medium or a product. The measurement results provided by the measuring devices are for example used in process automation for monitoring, controlling and / or regulating a process performed at an operating site. Measuring devices thus play a vital role in industry as well as in laboratories and a device not complying with the requirements specified for it, for example not complying with a specified measurement accuracy, can have serious consequences ranging from a damaged production process, production of defective products to potential hazards to people and / or situations.

[0003] To ensure that the measuring devices meet the requirements specified for them, they are periodically calibrated. Calibration is preferably performed on a specially designed calibration site that is able to provide reference values of the measured variable measured by the device with very high accuracy. A typical calibration process foresees determination of a measurement error of the device based on a measured value of the measured variable determined by the field device and a corresponding reference value provided. In case the measurement error exceeds a maximum allowed error, the device is considered non-compliant. Adjustment of the measurement indication, repair or replacement of the device is therefore required. If the measurement error does not exceed the maximum allowed error, compliance of the field device is declared and typically no further action is taken.

[0004] Calibrations are typically performed periodically after fixed calibration time intervals. As an example, fixed calibration time intervals recommended by the manufacturer of the device can be applied. These intervals are uniform for all devices of the same type, regardless of the measurement conditions to which the individual devices can be exposed during operation. They are typically set so short for safety reasons that statistically most devices, e.g. well above 90%, can be expected to be fully compliant at the end of their calibration time interval. Short calibration time intervals increase the costs involved in operating these devices. On the other hand, longer calibration time intervals increase the risk of operating non-compliant devices. In this context, the article "Calibration Intervals, A Manufacturer's Perspective" by David Deaver of Fluke Corporation, electronically published on December 11, 2012, describes a method of determining fixed calibration time intervals based on a trade-off between calibration costs and the risks involved in operating non-compliant devices.

[0005] As an alternative to fixed calibration time intervals, it is known in the art to apply individually determined calibration time intervals, wherein each next calibration time interval is individually determined for each device based on the measurement characteristics of the respective device determined during the present calibration. Corresponding methods are described, e.g., in EP 2 602 680 B1. These methods take into account that devices found to be just compliant during calibration can be expected to become non-compliant sooner than devices found to be fully compliant. Therefore, shorter calibration time intervals are applied to compliant devices showing lower degrees of compliance to reduce the risk of these devices becoming non-compliant during their operation until their next calibration, and longer calibration time intervals are applied to compliant devices showing higher degrees of compliance to reduce calibration costs.

[0006] Since the measurement characteristics of the measurement devices are typically determined during each calibration anyway, individually determined calibration time intervals can be determined with very little additional cost. However, scheduling and performing calibrations of measurement devices based on individually determined calibration time intervals does involve complex logic and can cause additional costs and inconveniences. One reason for this is that it is no longer possible to synchronize the calibrations of several devices of the same type to be performed simultaneously. This is particularly disadvantageous in applications where each calibration of one of the devices operating on an entire section of a production site has to shut down the section. This can lead to substantial additional costs beyond the costs involved in performing the calibration. SUMMARY

[0007] It is the object of the present invention to provide a method of operating a set of one or more measuring devices at an operating site and calibrating said devices, which allows further optimization of the calibration time intervals with respect to the risks and costs involved.

[0008] This object is achieved by a method of operating a set of one or more devices at an operating site and calibrating said devices, wherein each device is a measuring device and the calibration of said devices is run according to a schedule determined based on calibration time intervals determined for each of the devices, said method comprising the steps of:

[0009] a) during each calibration of each device: determining a degree of compliance of the respective device with requirements specified for this device, determining a recommended interval for the next calibration of the respective device based on said degree of compliance and determining a ratio of this recommended interval and the calibration time interval currently applied to this device,

[0010] b) reviewing the calibration time intervals based on said ratios and a set of pre-determined ratio ranges by performing for each device a procedure pre-determined for the ratio range, which comprises a ratio of the size of the ratios determined for the respective device or a replacement device replacing this device, and updating the calibration time interval currently applied to the respective device based on at least one of the following: rules defined for the respective ratio range and rules applicable to the respective device, and

[0011] c) determining a schedule of calibration times providing for the devices to be re-calibrated based on updated calibration time intervals determined for each of the devices and performing the next calibration of the devices according to the scheduled calibration times.

[0012] This method has the advantage that the review and update of the calibration time intervals is performed based on the degree of compliance determined individually for each of the devices. This allows the method to profit from the cost reduction potential and the risk reduction potential available based on the individually determined recommended intervals. At the same time, it allows the procedure pre-determined for each of the ratio ranges and rules to be applied to determine the updated calibration time intervals to be customized to the needs, requirements and circumstances prevailing at the operating site. Thus, the flexibility given with respect to the calibration time intervals of the devices having a higher degree of compliance can be used in the way most suitable for the operating site, as well as the synchronization of the calibrations. In addition, devices having a lower degree of compliance are identified and can be treated accordingly to reduce the risks.

[0013] Performing the review and update based on a small number of pre-defined ratio ranges has the advantage that the same procedure is applied to all devices falling into the same ratio range. This simplifies the logic required and facilitates and speeds up the execution of the method.

[0014] The first improvement comprises a method, wherein the set of ratio ranges comprises:

[0015] a lower ratio range comprising ratios ranging from zero to an upper limit of a lower range that is less than 1 or less than or equal to 0.75,

[0016] an intermediate range comprising ratios in which the recommended interval and the currently applied calibration time interval have the same order of magnitude or comprising ratios ranging from the upper limit of the lower range to an upper limit of the intermediate range that is greater than 1, less than or equal to 1.25 or less than or equal to 2, and

[0017] a higher ratio range comprising ratios in which the recommended interval is greater than or significantly greater than the currently applied calibration time interval or comprising all ratios that exceed a given threshold or a threshold given by the upper limit of the intermediate ratio range.

[0018] The improvement to the first improvement comprises a method, wherein the procedure performed with respect to all devices showing a ratio comprised in the lower ratio range comprises first procedure steps of performing at least one of the following: adjusting, maintaining and repairing the device, a second procedure step of recalibrating the device, re-determining the recommended interval and re-determining the ratio based on the re-determined recommended interval, and a third procedure step of determining an updated calibration time interval for the respective device or a replacement device replacing the device.

[0019] The improvement to the last-mentioned improvement comprises a method, wherein the procedure performed with respect to all devices showing a ratio comprised in the lower ratio range further comprises at least one of the following procedure steps:

[0020] a) performing the first, second and third procedure steps only with respect to devices showing a ratio exceeding a predefined threshold and replacing devices showing a ratio less than the threshold,

[0021] b) replacing the respective device in case the re-determined ratio belongs to the same ratio range as the previously determined ratio,

[0022] c) determining the updated calibration time interval for the respective device based on a rule applicable to the respective device or by determining a product of the re-determined recommended interval and a predefined constant and determining the updated calibration time interval to be an interval shorter than the product and longer than a minimum interval defined for the device, and

[0023] d) determining the updated calibration time interval for the respective replacement device based on a recommendation of the manufacturer of the replacement device.

[0024] The second improvement comprises a method, wherein:

[0025] The procedure performed with respect to all devices showing a ratio comprised in the intermediate range of ratios comprises at least one of the following steps:

[0026] a) determining an updated calibration time interval: al) based on at least one of: the recommended interval and the currently applied calibration time interval, a2) equal to the currently applied calibration time interval, equal to the recommended interval or equal to the longer or shorter of the currently applied calibration time interval and the recommended interval, a3) based on a rule taking into account at least one requirement, limitation or circumstance prevailing at the operating site, and / or a4) based on a rule applicable to the respective device, and

[0027] b) performing at least one of: maintaining the device, cleaning the device and replacing at least a part of the device, and

[0028] The procedure performed with respect to all devices showing a ratio comprised in the higher range of ratios comprises at least one of the following steps: determining an updated calibration time interval: cl) longer than the currently applied calibration time interval and shorter than or equal to the recommended interval determined for the respective device, c2) based on a rule stating at least one requirement, limitation or circumstance prevailing at the operating site, c3) equal to the longest interval or one of the longest intervals comprised in a predefined set of intervals comprising a limited number of intervals of different lengths shorter than or equal to the recommended interval determined for the respective device, c4) shorter than or equal to at least one of: a maximum allowed interval length defined for the respective device and a maximum allowed interval length defined for the operating site, and / or c5) based on a rule applicable to the respective device.

[0029] The third improvement comprises a method, further comprising the step of repeating the execution of the method for at least one further calibration cycle by:

[0030] performing the method steps of performing a calibration, determining a ratio, reviewing and updating the currently applied calibration time interval and scheduling and performing a next calibration,

[0031] wherein, during each cycle, following the first execution of the method, the currently applied calibration time interval is given by the corresponding updated calibration time interval determined during the preceding cycle.

[0032] The fourth improvement comprises a method, wherein:

[0033] each recommended interval is determined such that the recommended interval determined for a device showing a higher degree of compliance is longer than the recommended interval determined for a device showing a lower degree of compliance and vice versa,

[0034] Each calibration of each device arranged in the schedule is performed at a calibration time terminating an operation time interval during which the respective device has been operated at the operation site, and / or

[0035] Each arranged calibration time determined for one of the devices corresponds to an arranged interval of a length given by a time difference between the respective arranged calibration time and a calibration time at which the device or its predecessor has been calibrated immediately before the arranged calibration time in case the device has been replaced.

[0036] A fifth improvement comprises a method, further comprising the steps of:

[0037] For at least one or each calibration of at least one or all devices of the group, a data set is recorded immediately after the respective calibration, the data set comprising a device identification of the respective device and at least two or all of the following: recommended interval, currently applied calibration time interval, updated calibration time interval, arranged interval and operation time interval, and

[0038] At least one of the following steps is performed: determining at least one or based on at least one of the data sets an indicator indicating the performance of the method, recording at least one of the indicators, displaying at least one of the indicators, monitoring at least one of the indicators and issuing a notification when one of the monitored indicators exceeds a threshold value defined for the respective indicator.

[0039] An improvement to the fifth improvement comprises a method, wherein the indicators comprise at least one of the following:

[0040] A first asset value quantifying an increased cost associated with an update in which the currently applied calibration time interval is shortened such that the updated calibration time interval is shorter than the recommended interval,

[0041] A second asset value quantifying an increased risk associated with an update in which the currently applied calibration time interval is lengthened such that the updated calibration time interval is longer than the recommended interval,

[0042] A third asset value quantifying a cost reduction potential used by an update in which the currently applied calibration time interval is lengthened such that the updated calibration time interval is shorter than or equal to the recommended interval,

[0043] A fourth asset value quantifying a risk reduction potential used by an update in which the currently applied calibration time interval is shortened such that the updated calibration time interval is longer than or equal to the recommended interval,

[0044] a combined asset value given by only one of the first asset value, the second asset value, the third asset value and the fourth asset value defined for the respective data set,

[0045] at least one scheduled asset value, each scheduled asset value being determined in the same way as one of the first asset value, the second asset value, the third asset value, the fourth asset value and the combined asset value by replacing the updated calibration time interval applied in the respective determination by the scheduled interval,

[0046] at least one realized asset value, each realized asset value being determined in the same way as one of the first asset value, the second asset value, the third asset value, the fourth asset value and the combined asset value by replacing the updated calibration time interval applied in the respective determination by the operational time interval,

[0047] at least one calibration value, wherein each calibration value is determined based on or as a difference or an absolute value of the difference or a quotient of the operational time interval and the scheduled calibration time interval comprised in the respective data set, based on the interval comprised in one of the data sets,

[0048] at least one indicator value determined based on or as a difference or an absolute value of the difference or a quotient of the recommended interval and the currently applied calibration time interval, based on the interval comprised in one of the data sets,

[0049] at least one indicator value determined based on or as a difference or an absolute value of the difference or a quotient of the recommended interval and the updated calibration time interval, based on the interval comprised in one of the data sets,

[0050] at least one indicator value determined based on or as a difference or an absolute value of the difference or a quotient of the updated calibration time interval and the scheduled interval, based on the interval comprised in one of the data sets,

[0051] at least one indicator value determined based on or as a difference or an absolute value of the difference or a quotient of the updated calibration time interval and the currently applied calibration time interval, based on the interval comprised in one of the data sets, and

[0052] at least one further indicator.

[0053] The improvement to the fifth improvement further comprises the following steps:

[0054] Define at least one equipment group, wherein the equipment group includes at least one of the following: at least one equipment group each comprising a single specific piece of equipment; at least one equipment group each comprising equipment operating on a specific section of an operating station or on a section where one of the equipment that needs to be operated each time on that section is shut down when calibrated; an equipment group comprising all equipment operating at an operating station; and / or at least one other equipment group.

[0055] At least one group metric is determined for each of at least one device group, wherein each group metric is determined based on the average or absolute value of one of the determined metrics in a dataset of records for each device included in the device group over a given time period.

[0056] Perform at least one of the following steps: determine at least one group indicator for a number of consecutive given time periods, record at least one group indicator, display at least one group indicator, monitor at least one group indicator, and issue a notification when one of the monitored group indicators exceeds a threshold defined for the corresponding group-specific indicator.

[0057] The improvement to the fifth improvement also includes the following steps: based on at least one of the following: a first asset value, a second asset value, a third asset value, a fourth asset value, a combined asset value, an arranged asset value, a realized asset value, and / or at least one of a group of indicators each determined based on one of the first asset value, the second asset value, the third asset value, the fourth asset value, the combined asset value, the arranged asset value, or the realized asset value, to perform identification, quantification, provision, display, and monitoring of at least one of the following: increased risk, increased cost, risk reduction potential of use or non-use available according to the recommended interval, and cost reduction potential of use or non-use available according to the recommended interval.

[0058] Further improvements to the last mentioned improvement include the following steps: if one of the increased risk, increased cost, unused cost reduction potential and / or unused risk reduction potential exceeds a given threshold, then at least one root cause that caused the threshold to be exceeded is determined based on indicators and / or groups of indicators.

[0059] Further improvements to the last mentioned improvement include at least one of the following steps:

[0060] at least one of the increased risk, increased cost, unused risk reduction potential and / or unused cost reduction potential quantified based on at least one of the first asset value, the second asset value, the third asset value, the fourth asset value and / or at least one of the group indicators determined based on the first asset value, the second asset value, the third asset value and / or the fourth asset value exceeds a corresponding threshold value,

[0061] when at least one of the increased risk, increased cost, unused risk reduction potential and / or unused cost reduction potential quantified based on at least one of the scheduled asset values and / or at least one of the group indicators determined based on the scheduled asset values exceeds a value of the corresponding property quantified based on the first asset value, the second asset value, the third asset value and / or the fourth asset value by more than a predefined threshold value, the schedule is identified as the root cause, and

[0062] when at least one of the increased risk, increased cost, unused risk reduction potential and / or unused cost reduction potential quantified based on at least one of the realized asset values and / or at least one of the group indicators determined based on the realized asset values exceeds a value of the corresponding property quantified based on the scheduled asset values by more than a predefined threshold value, the schedule adherence of the executed calibration is identified as the root cause.

[0063] The last-mentioned improvement is further improved by at least one of the following steps:

[0064] Once the root cause has been identified, the method is modified by taking a corresponding countermeasure, and

[0065] when the schedule adherence has been identified as the root cause, at least one of the following is modified: at least one of the rules predetermined for the ratio range and at least one of the process steps of the process identified as the root cause, the schedule identified as the root cause and / or the calibration execution process.

[0066] The invention also comprises a calibration optimization system designed to execute at least one of the method steps of the method according to the fifth improvement, wherein:

[0067] the system comprises:

[0068] a memory,

[0069] an interface designed to receive data required by the system to store or determine and to store the data set in the memory,

[0070] A computing device and a computer program, the computer program being implemented on the computing device and causing the computing device to perform a determination of an indicator and / or a set of indicators based on a data set stored in a memory, and

[0071] wherein the system is designed to perform at least one of:

[0072] recording at least one of the indicators and / or the set of indicators,

[0073] providing at least one of the indicators and / or the set of indicators via an output of the system,

[0074] displaying at least one of the indicators and / or the set of indicators on a display comprised in or connected to the system,

[0075] monitoring at least one of the indicators and / or the set of indicators, and

[0076] issuing a notification when one of the monitored indicators and / or the monitored set of indicators exceeds a threshold value defined for it. BRIEF DESCRIPTION OF DRAWINGS

[0077] The invention and further advantages are explained in more detail using the individual figures of the drawing.

[0078] Figure 1 shows: a set of measuring devices operating on an operating site;

[0079] Figure 2 shows: an operating site, a calibration site and a calibration optimization system;

[0080] Figure 3 shows: a set of ratio ranges;

[0081] Figure 4 shows: a calibration cycle for a single device;

[0082] Figure 5 shows: an interval, a risk and a cost of a calibration cycle of a device;

[0083] Figure 6 shows: a set of formulas for determining an asset value based on an updated calibration time interval;

[0084] Figure 7 shows: an asset value determined for a continuous calibration cycle;

[0085] Figure 8 shows: a set of formulas for determining a scheduled asset value based on a scheduled interval;

[0086] Figure 9A set of formulas for determining an asset value based on an operating time interval is shown,

[0087] Figure 10 A group asset indicator determined based on a data set recorded during a continuous time period is shown. DETAILED DESCRIPTION

[0088] The invention provides a method of operating a group of one or more devices 1 at an operating site 3 and calibrating the devices 1. Figure 1 An example of a group of devices 1 operated at an operating site 3 is shown. The operating site 3 is for example an industrial site, for example a production or processing plant, a refinery, a steel mill or a laboratory. Each device 1 is a measuring device 1. Each device 1 is installed at a specific location on the operating site 3 at which it measures at least one measured variable during operation. The devices 1 can be any type of measuring device available on the market. Figure 1 An example is shown comprising a level measuring device measuring a level L of a product in a container 5, a flow meter measuring a flow F of a product through a pipe 7, a temperature measuring device measuring a temperature T of a gas, a liquid or an object, a measuring device comprising a sensor 9 measuring a pH value of a medium or a concentration C of a component included in a medium, and a pressure measuring device measuring a pressure p acting on the device. Obviously, more or less devices 1 and / or other types of devices 1 can be included in the group. As an option, at least one or all devices 1 can be connected to or in communication with a superior unit 11. As an example, the superior unit 11 can for example comprise a control system for at least one of managing a process performed at the operating site 3, process visualization and process monitoring.

[0089] The calibration of each of the devices 1 is performed according to a schedule determined based on a calibration time interval A determined for each of the devices 1. With respect to a new device 1 put into operation for the first time, the calibration time interval A can for example be determined as or based on a manufacturer recommendation provided by a manufacturer of the device 1. With respect to a device 1 already operated at the operating site 3, the calibration time interval A is given at least once by an interval currently applied to the respective device 1.

[0090] With respect to the calibration of each of the devices 1, a calibration method known in the art suitable for calibrating the respective type of device can be applied. These calibrations can for example be performed at the operating site 3 or at a calibration site 13 or sites 13 like the operating site 3 at which the devices 1 are operated and at which the calibration of the devices 1 is performed. Figure 2The illustrated specially built calibration site is performed on. As an example, a flow meter measuring the flow of a medium through a pipe 7 can be calibrated, for example, on a specially built calibration equipment designed to generate a flow of exactly determinable size through the flow meter installed on the equipment.

[0091] During each calibration of each of the devices 1 of the group, a degree of compliance of the respective device 1 to the requirements specified for the respective device 1 is determined. As an example, a degree of compliance to a measurement accuracy specified for the device 1 can be determined, for example, based on the measurement error of the device 1 determined during calibration. Based on the degrees of compliance determined during calibration of the devices 1, a recommended interval R is determined for the respective device 1. In this regard, any method of determining an individually determined next calibration time interval after which a particular device should be calibrated based on its degree of compliance to the specified requirements determined during the present calibration can be applied. As an example, the method described in EP 2 602 680 B1 incorporated herein by reference can be applied. According to this method, the optimized next calibration time after which a particular device should be calibrated is determined as the earlier or equal to the time at which the measurement error of the device will exceed a pre-determined maximum allowed error. This time is determined based on a Monte Carlo simulation performed based on the measurement errors of the respective devices 1 determined during at least two previously performed calibrations and a probability density function for determining the measurement error in the respective calibration solely due to the uncertainty inherent to the respective calibration process. Alternatively, other methods of providing individually determined recommended intervals R based on the degrees of compliance of the respective devices can be applied without departing from the scope of the invention described herein.

[0092] Irrespective of the applied method, the recommended intervals R are preferably determined such that the recommended interval R determined for a device 1 showing a higher degree of compliance is longer than the recommended interval R determined for a device 1 showing a lower degree of compliance and vice versa. As a result, each recommended interval R is individually determined and the recommended intervals R determined during successive calibrations of the same device 1 can be different. Each individually determined recommended interval R represents a device-specific optimal length of the next calibration time interval for the calibration of the device 1 in terms of reducing the risk that the device 1 will become non-compliant during its operation before its next calibration and in terms of reducing the calibration costs by increasing the length of the next calibration time interval to a degree at which it can be safely applied in view of the risk involved that the device 1 will become non-compliant before its next calibration due to its current degree of compliance.

[0093] Unlike the methods described in the prior art, the recommended interval R determined for each device 1 during each of its calibrations is not directly applied to schedule the next calibration of these devices 1. Instead, a ratio r := R / A is determined for each calibration by dividing the recommended interval R by the calibration time interval A(t n-1 ) currently applied to the corresponding device 1. In the case where the current calibration performed at the calibration time t n ) corresponds to the first calibration of the corresponding device 1, the calibration time interval A(t n-1 ) currently applied corresponds to the interval determined for a new device 1 as described above. In the case where the device 1 has not been calibrated at least once before, the calibration time interval A(t n-1 ) currently applied corresponds to the calibration time interval A(t n-1 ) applied to the device 1 immediately after the previous calibration performed at the calibration time t n-1 ) preceding.

[0094] In addition, the calibration time interval A(t n-1 ) currently applied is reviewed based on the ratio r determined for each of the devices 1 and on a set of pre-determined ranges of ratios I, II, III. This is done by performing for each device 1 a pre-determined procedure of the range of ratios I, II, III comprising the ratios of a size of the ratio r determined for the corresponding device 1 or for a replacement device 1 of the corresponding device 1, and by updating the calibration time interval A(t n-1 ) currently applied to the corresponding device 1 based on rules defined for the corresponding range of ratios I, II, III and / or based on rules applicable to the corresponding device 1.

[0095] The set of ranges of ratios preferably comprises a number of non-overlapping ranges of ratios I, II, III greater than or equal to two. Figure 3 An example is shown comprising a set of three ranges of ratios. The lower range of ratios I comprises the ratios r ranging from zero to an upper limit LI of the lower range of ratios I less than 1, preferably less than or equal to 0.75. The intermediate range II comprises the ratios r for which the recommended interval R and the calibration time interval A(t n-1 ) currently applied have the same order of magnitude. As an example, the intermediate range II can vary from the upper limit LI of the preceding lower range I to an upper limit L2 of the intermediate range II greater than 1 and preferably less than or equal to 1.25 or less than or equal to 2. The higher range of ratios III comprises the ratios r for which the recommended interval R is greater, preferably significantly greater, than the calibration time interval A(t n-1 ) currently applied. As an example, the higher range of ratios III can comprise all the ratios r exceeding a given threshold, for example the threshold given by the upper limit L2 of the intermediate range II. As an alternative option, the higher range of ratios III can be defined by a lower limit L3 of the higher range of ratios III greater than 1, preferably greater than or equal to 1.25 or greater than or equal to 2. Figure 3At least one of the illustrated ratio ranges I, II, III is subdivided into two or more ratio ranges and different procedures can be predetermined for each of these ranges.

[0096] Irrespective of the number of ratio ranges I, II, III applied and of the upper and / or lower limits LI, L2, the procedure is preferably determined on the basis of the magnitude of the ratio r comprised in the respective ratio range I, II, III and, as an option, on the basis of requirements prevailing at the operating site 3.

[0097] As an example, the procedure performed with respect to all devices 1 showing a ratio r comprised in the lower ratio range I preferably comprises a first procedure step of performing at least one of the following: adjustment, maintenance and repair of the device 1. Adjustment of the device 1 is preferably performed on the basis of calibration data obtained during calibration and can for example comprise adjustment of the offset, gain and / or span of the measurement indication of the device 1. Maintenance can for example comprise at least one of the following: cleaning of the device 1, performing a visual inspection, replacing at least one part of the device 1 that is subject to wear and tear, and performing special tests or checks of individual components of the device 1. Repair of the device can for example comprise repair or replacement of at least one defective component of the device 1. This is followed by a second procedure step comprising the steps of recalibrating the device 1, redetermining the recommended interval R and redetermining the ratio r on the basis of the redetermined recommended interval R. As an option, the procedure can require replacement of the device 1 when the redetermined recommended calibration time R is shorter than a minimum interval CTI min defined for the device 1. In these cases, it is not necessary to redetermine the ratio r. As a further option, the procedure can require application of the first procedure step and the second procedure step only to devices 1 showing a ratio r that exceeds a predefined threshold value r min and replacement of devices 1 showing a ratio r that is smaller than this threshold value r min As a further option, the procedure can require replacement of the device 1 in all cases in which the redetermined ratio r belongs to the same ratio range I as the previously determined ratio r. Finally, as a third procedure step, the currently applied calibration time interval A(t n ) is updated on the basis of the rules defined for the lower ratio range I and / or on the basis of rules applicable to the respective device 1. n-1

[0098] The rules applicable to the respective device 1 can for example be the following rules: According to which the updated calibration time interval A(t n ) is set equal to the currently applied calibration time interval A(t n-1 ​) or a predetermined fixed calibration time interval predetermined for the respective device 1 or a class of devices 1 comprising the respective device 1. It is possible, for example, to apply a rule applicable to the respective device 1 to all devices 1 for which the respective rule is applicable, irrespective of the ratio r determined for them. In that case, it is possible to include the same rule in each of the processes defined for the ratio ranges I, II, III. On the basis of the rule(s) applicable to the respective device 1, there is always the possibility that at least one of the updated calibration time intervals A(t n ) thus determined can be longer than the recommended interval R determined for the respective device 1.

[0099] The rule defined for the lower ratio range I preferably requires the updated calibration time interval A(t n ) to be determined on the basis of the re-determined recommended interval R in all cases in which the device 1 has not been replaced. In this respect, it is possible, for example, to determine the updated calibration time interval A(t n ) on the basis of a product given by multiplying the re-determined recommended interval R by a pre-defined constant, for example, by determining the updated calibration time interval A(t n ) to be equal to an interval shorter than this product and longer than the minimum interval CTI min defined for the respective device 1. In addition, the rule can require the updated calibration time interval A(t n ) to be determined as described above with respect to determining the initial calibration time interval A for a new device 1 in all cases in which the device 1 has been replaced by a new replacement device 1.

[0100] The intermediate ratio range II comprises ratios r for which the recommended interval R and the currently applied calibration time interval A have the same order of magnitude. Since the recommended interval R is determined on the basis of the conformity of the respective device 1, it is sufficient for the process defined for the intermediate ratio range II to include only the step of updating the calibration time interval A. The corresponding rule defined for the intermediate ratio range II preferably requires the updated calibration time interval A(t n-1 ) to be determined on the basis of the recommended interval R and / or the currently applied calibration time interval A(t n ). As an example, it is possible to determine the updated calibration time interval A(t n ) to be equal to the currently applied calibration time interval A(t n-1 ), to be equal to the recommended interval R or to be equal to the currently applied calibration time interval A(t n-1) and the longer, the shorter or the average of the two. As an option, the rules defined for the intermediate rate range II can be defined to additionally account for at least one requirement, limitation or situation prevailing at the operating site and / or at least one special requirement of at least one of the devices 1 of the group. Even if a single step of updating the currently applied calibration time interval A based on the rules defined for the intermediate rate range II and / or based on rules applicable to the respective device 1 is already sufficient, the procedure II defined for the intermediate rate range can comprise further steps, e.g. steps directed to enhancing the long-term stability of operating the respective device 1, like e.g. at least one of the following: maintenance of the device 1, cleaning of the device 1 and replacement of at least one part subject to wear and tear.

[0101] The higher rate range III comprises rates r, wherein the recommended interval R is much longer than the currently applied calibration time interval A. Since the recommended interval R is determined based on the compliance of the respective device 1, it is sufficient for the procedure defined for the higher rate range III to comprise only a step of updating the currently applied calibration time interval A based on the rules defined for the higher rate range III and / or based on rules applicable to the respective device 1.

[0102] The rules defined for the higher rate range III preferably require each updated calibration time interval A(t n ) to be determined to be longer than the currently applied calibration time interval A(t n-1 ) and shorter than or equal to the recommended interval R determined for the respective device 1. As a further option, the flexibility given by extending from the currently applied calibration time interval A(t n-1 ) to the range given by the recommended interval R is preferably used to optimize the efficiency and cost utility of the execution of the calibration of the group of devices 1. In this regard, the rules defined for the higher rate range III can be defined to additionally account for at least one requirement, limitation or situation prevailing at the operating site, like e.g. the flexibility and availability of calibration times at which the calibration of the respective device 1 can be performed and / or special requirements of at least one of the devices 1 of the group. As an example, the rules defined for the higher rate range III can require that the calibration time interval A(t n ) for all devices 1 or for at least one or more specific devices 1 is always determined to be longer than a given minimum interval CTI min and / or shorter than a given maximum interval CTI max . As another example, the rules defined for the higher rate range III can require that the updated calibration time interval A(t nThe time interval corresponds to the periodic downtime between the work sections at the operating station, during which calibration of equipment 1 operating in these work sections can be performed without interfering with the process performed at operating station 3. Alternatively, the updated calibration time interval A(t) is... n The calibration time interval A(t) can be determined, for example, based on a finite set of intervals of varying lengths. In this case, each updated calibration time interval A(t) n The interval is determined to be one of the longest intervals included in the set of intervals that is shorter than or equal to the recommended interval R determined for the corresponding device 1. This will update the calibration time interval A(t) accordingly. n The variety of interval lengths is reduced to a finite number of lengths included in the interval set. This is particularly advantageous when the group includes a large number of devices 1, such as more than 10 or 100 or even more than 1000 devices 1, because it allows the calibration of a larger number of devices 1 to be synchronized.

[0103] As an alternative or other option, the updated calibration time interval A(t) n The interval can be determined to be shorter than or equal to at least one of the following: the maximum permissible interval length defined for the corresponding device 1 and the maximum permissible interval length defined for the operation site 3. This reduces the risk that either device 1 to which the rule is applied will become non-compliant during operation prior to its next calibration.

[0104] Without departing from the scope of the invention, other rules can be applied or given by a combination of rules defined for one of the ratio ranges I, II, III and rules applicable to the corresponding device 1, other sets of ratio ranges and / or other processes.

[0105] Follow the updated calibration time interval A(t) n After review and determination, based on the updated calibration time interval A(t) n ) to determine the calibration time t for each device 1, in which the corresponding device 1 should be recalibrated at that time. S The schedule. This provides the interval S for the arrangement of corresponding device 1 or the replacement device 1 for corresponding device 1, which is composed of the calibration time t of the arrangement for corresponding device 1. S With calibration time t n Given the time difference between them, at the calibration time t n The corresponding device 1—or its predecessor if it has been replaced—was most recently calibrated at the scheduled time t. S Previously calibrated. As an option, the calibration time t is scheduled. SAnd therefore the interval S, arranged in the same way, is preferably determined by further explanation of at least one constraint that is generally present with respect to at least one of the following: the specific device 1, the operating site 3, and the calibration site 13, which governs the flexibility and availability of calibration time capable of performing calibration of the corresponding device 1 or a replacement device 1. Finally, the next calibration of device 1 is performed according to the previously determined schedule.

[0106] This method of operating and calibrating the group of measuring devices 1 has the advantages mentioned above. The method can be terminated after device 1 has been calibrated according to a previously determined schedule. Alternatively, the method can be repeated as many calibration cycles as desired or required. In that case, each cycle includes performing calibration as described above, determining the ratio r, reviewing and updating the calibration time interval A(t) for the current application. n-1 The method steps for scheduling and performing the next calibration are also described. Therefore, in each cycle immediately following the first execution of this method, the currently applied calibration time interval A(t) is... n-1 The corresponding updated calibration time interval A(t) determined during the previous cycle. n Given.

[0107] Repeated execution of this method has the following advantages: due to the updated calibration time interval A(t) n ) compared to the current application's calibration time interval A(t) n-1 For all those devices with longer calibration cycles, each calibration cycle helps reduce the overall calibration cost. Additionally, due to the identified lower compliance and the correspondingly shorter updated calibration interval A(t) determined for them... n All symbols of device 1, each calibration cycle helps reduce the risk of operation not conforming to device 1. Figure 4 It shows that at time t n-1 An example of a calibration cycle for a single device 1 that has recently been put into operation. This device 1 operates according to the current calibration time interval A(t) applied to device 1. n-1 The scheduled calibration time t n Calibrated. The calibration time interval A(t) n-1 A(t) is the initial interval determined for new device 1 or the updated calibration time interval determined during the previous calibration cycle. n-1 In the latter case, the starting time t n-1 The calibration time t corresponding to the most recent calibration of device 1 n-1 At calibration time t n The calibration process terminates at a given calibration time t. n With start time t n-1 The time difference between them is the length of the ongoing operation time interval OTI. Based on the calibration time interval A(t) of the current application. n-1) and the scheduled calibration time t n The calibration performed, the recommended interval R, the updated calibration time interval A(t n ) and the scheduled calibration time t Figure 4 corresponding to the scheduled interval S of the schedule is determined. Next, the device 1 is re-calibrated at the next calibration time t S , thereby terminating the next operation time interval OTI of length given by the time difference between the calibration time t n+1 n+1 n

[0108] In real life, it is not always possible to perform the calibration at the exact point in time given by the scheduled calibration time t S . This can have various reasons, like e.g. a varying workload of the technician performing the calibration, unexpected delays, e.g. due to downtime of the calibration site 13, unexpected accelerations, e.g. due to free calibration capacity available at the calibration site 13, or special situations occurring at the operation site 3 affecting the execution of the calibration. Therefore, the length of the operation time interval OTI and the corresponding scheduled interval S is not necessarily identical.

[0109] Therefore, the method provides an interval set comprising the recommended interval R following each calibration of each device 1, the current applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ), the scheduled interval S and the operation time interval OTI. Figure 5 An example of a single interval set is shown, wherein all intervals comprised in the set are different. When considering only a single device 1 or when the constraints of the availability and flexibility of the calibration times and additional costs caused by these constraints are ignored or non-existent, the calibration cost decreases with the length of the operation time t at which the device 1 is operated as indicated by the arrow a shown in Figure 5 Additionally, the risk that each device 1 becomes non-compliant during operation increases with the length of the operation time t as indicated by the arrow b in Figure 5 Based on this, the recommended interval R constitutes the optimal interval length for the respective device 1 with respect to both the risks and the costs involved.

[0110] ​​​The difference between the individual intervals included in each cluster is only appropriate and justified by the prevailing circumstances and conditions at the operating site 3, assuming the best execution of each method step and process and rule best suited for application. By way of example, the additional costs caused by an operating time interval OTI that is shorter than the corresponding recommended interval R can be justified, for example, by the costs saved by reducing the downtime of the operating site 3 needed to perform the calibration and / or by the savings achieved by the synchronization of the calibrations of several devices 1 thereby. In practice, the determination of the processes and rules best suited for application is a complex task. In addition, the logic involved in performing the calibration, especially with respect to a group comprising a large number of devices 1, is quite complex. Therefore, there is the possibility that the execution of one or more method steps and pre-determined processes and rules can be further improved to profit from or realize the full potential of the method, in particular the full risk reduction potential and / or the full cost reduction potential available according to the recommended intervals R. This can be done by modifying the execution of at least one method step, at least one rule and / or at least one process. Identifying the potential that is not currently used by the method and / or determining the modification(s) needed to better exploit the potential is not an easy task. One reason for this is that the potential available during each update of the calibration time interval of each device 1 depends on the length of the recommended interval R at that time. This length depends not only on the long-term measurement characteristics of the respective device 1, but also on the environmental conditions to which the device 1 has been exposed during operation and on unexpected events that have affected the measurement characteristics of the device 1. Therefore, the recommended intervals R determined for the same device 1 during successive calibrations can be different, which makes it difficult to decide whether a modification of the method is worthwhile.

[0111] As an option, the method is thus further improved by recording a data set k following each respective calibration, the data set k comprising the device identification d of the respective device 1 and at least two, preferably all, of the following: at least one of the devices 1 of the group, preferably each calibration of at least one of the devices 1 of the group, preferably the recommended interval R of all devices 1 of the group, the calibration time interval A(t n-1 ) currently applied, the updated calibration time interval A(t n ), the scheduled interval S and the operating time interval OTI. As an option, each data set k preferably also comprises the corresponding calibration time t n In addition, at least one indicator indicating the execution of the method is determined based on at least one of the data sets k.

[0112] As Figure 2The data sets k can for example be stored in the calibration optimization system 17, which comprises a computing device 19, a memory 15 and an interface 21 designed to store or determine the data required by the receiving system 17 and to store the data sets k. The data is sent to the system 17, which then stores the data sets k in the memory 15. The computing device 19 is designed to execute a computer program SW which is implemented on said computing device 19 and which causes the computing device 19 to perform the determination of the indicators based on the data sets k stored in the memory 15. As an option, at least one of the indicators, preferably all of the indicators, are recorded, displayed and / or monitored by the system 17. As a further option, a notification is preferably issued when one of the indicators being monitored exceeds a threshold value defined for the respective indicator. In this respect, the indicators are for example recorded in the memory 15 and / or displayed by a display 23 comprised in or connected to the calibration optimization system 17. The system 17 is preferably designed to monitor at least one of the indicators and / or comprises an output 25 designed to provide the indicators and / or to issue the notifications.

[0113] The risk and cost considerations are Figure 5 The calibration time interval is updated as a function of the operating time t as shown, to equal the recommended interval R with the full potential of the interval optimization that can be safely applied according to the recommended interval R. Where the currently applied calibration time interval A(t n-1 ) is extended so that the updated calibration time interval A(t n ) is shorter than or equal to the recommended interval R, the update utilizes the cost reduction potential available according to the recommended interval R. Where the currently applied calibration time interval A(t n-1 ) is extended so that the updated calibration time interval A(t n ) exceeds the recommended interval R, the update incurs increased risk. On the other hand, where the currently applied calibration time interval A(t n-1 ) is shortened so that the updated calibration time interval A(t n ) is longer than or equal to the recommended interval R, the update utilizes the risk reduction potential available according to the recommended interval R. Where the currently applied calibration time interval A(t n-1 ) is shortened so that the updated calibration time interval A(t n ) is shorter than the recommended interval R, the update incurs increased cost.

[0114] The indicators preferably comprise at least one asset value V(k) determined for each data set k. Examples of currently preferred asset values and examples of formulas for their determination are shown in Figure 6 These asset values V(k) preferably comprise first asset values V1(k) quantifying the risk associated with the calibration time interval A(tn-1 ) is shortened such that the updated calibration time interval A(t n ) is shorter than the recommended interval R. In Figure 6 In the example shown, the first asset value V1(k) is given by V1(k): = 1 - A(t n-1 ) / A(t n ) for all data sets k, where the recommended interval R is longer or equal to the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is shorter than the currently applied calibration time interval A(t n-1 ), and given by V1(k): = R / A(t n )-1 for all data sets k, where the recommended interval R is shorter than the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is shorter than the recommended interval R.

[0115] As a further or alternative option, the asset value V(k) preferably comprises a second asset value V2(k) quantifying an increased risk associated with an update in which the currently applied calibration time interval A(t n-1 ) is lengthened such that the updated calibration time interval A(t n ) is longer than the recommended interval R. In Figure 6 In the example shown, the second asset value V2(k) is given by V2(k): = A(t n ) / R-1 for all data sets k, where the recommended interval R is longer than the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is longer than the recommended interval R, and given by V2(k): = A(t n ) / A(t n-1 ) for all data sets k, where the recommended interval R is shorter than or equal to the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is longer than the currently applied calibration time interval A(t n-1 ).

[0116] As a further or alternative option, the asset value V(k) preferably comprises a third asset value V3(k) quantifying an increased risk associated with an update in which the currently applied calibration time interval A(t n-1 ) is lengthened such that the updated calibration time interval A(t nThe cost reduction potential of an update shorter than or equal to the recommended interval R. In Figure 6 In the example shown, the third asset value V3(k) is given by V3(k):=[A(t n )-A(t n-1 )] / [R-A(t n-1 )] for all data sets k, where the recommended interval R is longer than the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is greater than or equal to the currently applied calibration time interval A(t n-1 ) and shorter than or equal to the recommended interval, and is given by V3(k):=100% for all data sets k, where the updated calibration time interval A(t n ) is equal to the recommended interval R and equal to the currently applied calibration time interval A(t n-1 ).

[0117] As an additional or alternative option, the asset values V(k) preferably include a fourth asset value V4(k) quantifying the risk reduction potential of an update where the currently applied calibration time interval A(t n-1 ) is reduced such that the updated calibration time interval A(t n ) is longer than or equal to the recommended interval R. In Figure 6 In the example shown, the fourth asset value V4(k) is given by V4(k):=[A(t n-1 )-A(t n )] / [A(t n-1 )-R] for all data sets k, where the recommended interval R is shorter than the currently applied calibration time interval A(t n-1 ) and the updated calibration time interval A(t n ) is longer than or equal to the recommended interval R and shorter than or equal to the currently applied calibration time interval A(t n-1 ), and is given by V4(k):=100% for all data sets k, where the updated calibration time interval A(t n ) is equal to the recommended interval R and equal to the currently applied calibration time interval A(t n-1 ).

[0118] Based on the distinction of the cases applied in the determination of these asset values V1(k), V2(k), V3(k), V4(k), only one of the four asset values V1(k), V2(k), V3(k), V4(k) can be used for each data set k. This has the advantage that all four asset values V1(k), V2(k), V3(k), V4(k) can be summarized in a combined asset value VC(k) given by the combination of only one of the four asset values V1(k), V2(k), V3(k), V4(k) for the respective data set k. These combined asset values VC(k) are preferably displayed in the diagram shown in Figure 7 wherein the first asset value V1(k) representing the increased cost is displayed as a positive percentage exceeding 100%, wherein the second asset value V2(k) representing the increased risk is displayed as a negative percentage below -100%, wherein the third asset value V3(k) representing the cost reduction potential used by the respective update is displayed as a positive percentage ranging from 0% to 100%, and wherein the fourth asset value V4(k) representing the risk reduction potential used by the respective update is displayed as a negative percentage ranging from 0% to -100%. Obviously, other display forms can be used. As an example, two diagrams can be displayed, one diagram comprising the increased risk V2(k), the used cost reduction potential V3(k) and the increased cost V1(k) determined for the data set k, wherein the recommended interval R is greater than or equal to the currently applied interval A(t n-1 ), and a second diagram comprising the increased cost V1(k), the used risk reduction potential V4(k) and the increased risk V2(k) determined for the data set k, wherein the recommended interval R is smaller than the currently applied interval A(t n-1 ).

[0119] Obviously, other ways of determining these asset values conveying the same, equivalent, corresponding or related information content can be applied without departing from the scope of the present invention. As an example, the unused cost reduction potential can be applied instead of the used cost reduction potential, and the unused risk reduction potential can be applied instead of the used risk reduction potential, for example.

[0120] As a further option, the indicator preferably comprises at least one scheduled asset value VS1(k), VS2(k), VS3(k), VS4(k), VCS(k) determined in the same way as one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and the combined asset value VC(k) by replacing the updated calibration time interval A(t n ) applied in the respective determination by a scheduled interval S as shown in Figure 8 Alternatively or in addition thereto, the indicator preferably comprises at least one scheduled asset value VS1(k), VS2(k), VS3(k), VS4(k), VCS(k) determined in the same way as one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and the combined asset value VC(k) by replacing the updated calibration time interval A(t n ) applied in the respective determination by a scheduled interval S as shown inFigure 9 the updated calibration time interval A(t n ) applied in the respective determination is replaced by the operating time interval OTI as illustrated in the same way as one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and the combined asset value VC(k) is determined.

[0121] As an alternative or additional option, the indicators preferably comprise at least one calibration value W(k) indicating the compliance of the schedule on which the execution of the respective calibration is based with the schedule it is executed. Each calibration value W(k) is determined based on or as the difference or the absolute value of the difference between the operating time interval OTI and the scheduled calibration time interval S comprised in the respective data set k, based on the interval comprised in one of the data sets k, e.g. given by W(k):=OTI-S. As an alternative option, the calibration value W(k) can be determined as or based on the quotient given by the operating time interval OTI divided by the scheduled interval S comprised in the respective data set k, e.g. determined by W(k):=OTI-S.

[0122] As an alternative or additional option, the indicators preferably comprise at least one further indicator value determined based on the interval comprised in one of the data sets k. An example is an indicator value determined for at least one or each data set k based on or as the difference or the absolute value of the difference or the quotient between 1) the recommended interval R and the currently applied calibration time interval A(t n-1 ), 2) the recommended interval R and the updated calibration time interval A(t n ), 3) the updated calibration time interval A(t n ) and the scheduled interval S, or 3) the updated calibration time interval A(t n ) and the currently applied calibration time interval A(t n-1 ).

[0123] At least one of these indicators, preferably more or all of the above listed indicators, are preferably determined for the data sets k recorded during the successive calibration cycles of at least one, preferably all, devices 1 and are also preferably displayed. Figure 7 An example of the combined asset value VC(k) of the data sets k recorded for the calibration of the same device 1 at four different calibration times t1,..., t4 is shown, wherein each time the updated calibration time A(t n ) differs from the currently applied calibration time interval A(t n-1). In this example, the update performed at time t1 causes an increase in cost represented by the first asset value V1(k(t1)). The update performed at time t2 utilizes the percentage of cost reduction potential available at time t2 given by the third asset value V3(k(t2)). The update performed at time t3 utilizes the percentage of risk reduction potential available at time t3 given by the fourth asset value V4(k(t3)). The update performed at time t4 causes an increase in risk given by the second asset value V2(k(t4)).

[0124] As a further option, at least one group of devices is preferably defined and at least one group indicator is determined for at least one of the groups of devices. The groups of devices preferably comprise at least one of at least one group of devices each comprising a single specific device 1, at least one group of devices each comprising devices 1 of a given class or type, at least one group of devices each comprising devices 1 operating on a specific work section at the operating site 3, such as e.g. a work section requiring to be closed each time one of the devices 1 operating on this work section is calibrated, a group of devices comprising all devices 1 operating at the operating site 3 and / or at least one other group of devices. Preferably, each of the group indicators is determined preferably based on an average value or an absolute value of an average value of one of the previously described indicators determined as each of the data sets k recorded for the devices 1 comprised in the given group of devices during a given time period Ati. Each of these group indicators is preferably determined, recorded, displayed and monitored, and a notification is preferably issued when one of the monitored group indicators exceeds a threshold value defined for the respective group indicator.

[0125] With respect to each of the asset values V(k) comprising the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k), the combined asset value VC(k), the arranged asset value VS(k) and the implemented asset value VI(k), a corresponding group asset indicator V G Preferably determined by the user of the method or by the calibration optimization system 17 based on or as an average value of the respective asset values V(k) determined for the data sets k := 1,..., m recorded for the devices 1 comprised in the respective group of devices during a given time period Ati, e.g. determined by

[0126]

[0127] As Figure 10 indicated, the group specific asset indicators V GPreferably determined and displayed in relation to Figure 7 The diagrams shown are of the same type. Preferably, the same determination and representation are applied to the arranged asset values ​​VS1(k), VS2(k), VS3(k), VS4(k) and the implemented asset values ​​VI1(k), VI2(k), VI3(k), VI4(k).

[0128] The specific calibration index W for each group is relative to the calibration value W(k). G Preferably, the calibration value W(k) is determined by the user of the method or by the calibration optimization system 17 as the average of the calibration values ​​W(k) or as the average of the absolute values ​​of the calibration values ​​W(k) determined for the dataset k included in the corresponding group of the dataset. Similarly, this determination of group-specific indicators can also be applied relative to other indicator values ​​mentioned above.

[0129] Based on at least one of the following: at least one of the asset values ​​V(k) and a group-specific asset indicator V G At least one of the increased risks, increased costs, and the potential for risk reduction from use or unuse, and / or the potential for cost reduction from use or unuse, based on the recommended interval R determined during the respective calibration period, are preferably identified, quantified, and / or monitored. The unused cost reduction potential is given by the difference between the available full potential (shown as +100%) and the cost reduction potential from use. The unused risk reduction potential is given by the difference between the available full potential (shown as -100%) and the risk reduction potential from use. This step is preferably performed at the device level regarding at least one of the devices 1, at the group level regarding devices included in one of the device groups, and / or at the site level regarding all devices 1 operating at operating site 3. This can be performed by the user of the method or by the calibration optimization system 17. In the latter case, the increased risks, increased costs, and / or the potential for use or unuse thus determined are preferably provided and / or displayed by the calibration optimization system 17.

[0130] When increased risk, increased cost, and / or unused potential exceeding a given threshold are identified, it is preferable to determine at least one root cause that caused the threshold to be exceeded based on indicators and / or groups of indicators.

[0131] As an example, at least one of the increased risk, the increased cost, the unused cost reduction potential and / or the unused risk reduction potential quantified based on the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and / or at least one of the group indicators determined based on the first asset value V1(k), the second asset value V2(k), the third asset value V3(k) and / or the fourth asset value V4(k) exceeds a respective threshold value, e.g. at least one of the predefined rules for the rate ranges I, II, III and / or at least one of the process steps of the process is determined as root cause.

[0132] As another option, at least one of the increased risk, the increased cost, the unused risk reduction potential and / or the unused cost reduction potential quantified based on at least one of the realized asset values VS1(k), VS2(k), VS3(k), VS4(k) and / or at least one of the group indicators determined based on the realized asset values VS1(k), VS2(k), VS3(k), VS4(k) exceeds a value of the corresponding property quantified based on the first asset value V1(k), the second asset value V2(k), the third asset value V3(k) and / or the fourth asset value V4(k) greater than a predefined threshold value, the schedule is preferably identified as root cause.

[0133] As another option, at least one of the increased risk, the increased cost, the unused risk reduction potential and / or the unused cost reduction potential quantified based on at least one of the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) and / or at least one of the group indicators determined based on the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) exceeds a value of the corresponding property quantified based on the scheduled asset values VS1(k), VS2(k), VS3(k), VS4(k) greater than a predefined threshold value, the schedule adherence of the calibrated execution is preferably identified as root cause.

[0134] Once the root cause has been identified, a corresponding countermeasure is preferably taken. As an example, the countermeasure can e.g. include, when the schedule adherence has been identified as root cause, modifying at least one of the at least one of the predefined rules for the rate ranges I, II, III and / or at least one of the process steps of the process identified as root cause, modifying the schedule identified as root cause or modifying the calibration execution process.

[0135] Hence, each different type of indicator and the corresponding group specific indicators constitute a powerful tool for monitoring the execution of the method and for iteratively improving the realized method steps to further profit from the full potential of the method in the most suitable way for the application.

[0136] List of reference signs

[0137] 1 measuring device 15 memory

[0138] 2 operating station 17 calibration optimization system

[0139] 5 container 19 computing device

[0140] 7 pipeline 21 interface

[0141] 9 sensor 23 display

[0142] 11 superior unit 25 output

[0143] 13 calibration station

Claims

1. A method of operating a group of one or more devices (1) and calibrating said devices (1) at an operating site (3), wherein: Each device (1) is a measuring device (1) and runs a calibration of said device (1) according to a schedule determined on the basis of a calibration time interval A determined for each of said devices (1), said method comprising the steps of: a) during each calibration of each device (1): determining the degree of compliance of the respective device (1) with respect to the requirements specified for this device (1), determining a recommended interval R for the next calibration of the respective device (1) on the basis of said degree of compliance and determining the ratio r of said recommended interval R and the calibration time interval A(t n-1 ) currently applied to this device (1), b) during each calibration of each device (1): determining the degree of compliance of the respective device (1) with respect to the requirements specified for this device (1), determining a recommended interval R for the next calibration of the respective device (1) on the basis of said degree of compliance and determining the ratio r of said recommended interval R and the calibration time interval A(t n-1 ) currently applied to this device (1), c) during each calibration of each device (1): determining the degree of compliance of the respective device b) reviewing the calibration time interval A based on said ratio r and a set of predetermined ratio ranges I, II, III by performing for each device (1) a predetermined procedure for said ratio ranges I, II, III comprising ratios of the magnitude of said ratio r determined for the respective device (1) or for a replacement device (1) replacing said device (1) and updating the calibration time interval A (t n-1 ) currently applied to the respective device (1) based on at least one of the rules defined for the respective ratio ranges I, II, III and rules applicable to the respective device (1), and c) determining a schedule of calibration times t n at which the devices (1) should be recalibrated based on the updated calibration time intervals A(t S ) determined for each of the devices (1) and performing the next calibration of the devices (1) according to the schedule of calibration times t S . wherein said set of ratio ranges I, II, III comprises: a lower ratio range I comprising ratios r ranging from zero to an upper limit LI of said lower ratio range I lower than 1, an intermediate ratio range II, the intermediate ratio range II comprising ratios r, wherein the recommended interval R and the currently applied calibration time interval A(t n-1 ) have the same order of magnitude, or comprising ratios r ranging from the upper limit LI of the lower ratio range I to an upper limit L2 of the intermediate ratio range II being greater than 1, less than or equal to 2, and Higher ratio range III, wherein the recommended interval R is greater than the calibration time interval A(t) of the current application. n-1 The ratio r of ), or all ratios r that exceed a given threshold or a threshold given by the upper limit L2 of the intermediate ratio range II.

2. The method of claim 1, wherein, said lower ratio range I comprising ratios r ranging from zero to said upper limit LI of said lower ratio range I lower than or equal to 0.

75.

3. The method of claim 1, wherein, said intermediate ratio range II comprising ratios r from said upper limit LI of said lower ratio range I to an upper limit L2 of said intermediate ratio range II greater than 1, lower than or equal to 1.

25.

4. The method of claim 1, wherein: The procedure performed with respect to all devices (1) showing a ratio r comprised in said lower ratio range I comprises a first procedure step of performing at least one of: an adjustment, a maintenance and a repair of said device (1); a second procedure step of recalibrating said device (1), re-determining said recommended interval R and re-determining said ratio r based on said re-determined recommended interval R; and a third procedure step of determining for a respective device (1) or for a replacement device (1) replacing said device (1) said updated calibration time interval A(t n ).

5. The method of claim 4, wherein: said process performed with respect to all devices (1) showing ratios r comprised in said lower ratio range I further comprises at least one of the following process steps: a) only devices (1) showing a ratio r exceeding a predefined threshold r min perform the first, second and third process steps and replace devices (1) showing a ratio r smaller than this threshold r min perform the first, second and third process steps and replace devices (1) showing a ratio r smaller than this threshold r b) in case the re-determined ratio r belongs to the same ratio range I as the previously determined ratio r, replacing the corresponding device (1), c) determining the updated calibration time interval A(t) for the respective device (1) based on said rules applicable to the respective device (1) or by determining a product of said re-determined recommendation interval R and a pre-defined constant and determining said updated calibration time interval A(t n ) to be equal to an interval shorter than said product and longer than a minimum interval CTI min defined for said device (1), and n ​ d) determining the updated calibration time interval A(t) for the respective replacement device (1) based on recommendations of the manufacturer of the replacement device (1). n ).

6. The method according to any one of claims 1 to 5, wherein: said process performed with respect to all devices (1) showing ratios r comprised in said intermediate ratio range II comprises at least one of the following steps: a) Determine the updated calibration time interval A(t) n ): a1) Based on at least one of the following: the recommended interval R and the calibration time interval A(t) of the current application. n a2) is equal to the calibration time interval A(t) of the current application. n-1 ), equal to the recommended interval R or equal to the calibration time interval A(t) of the current application. n-1 a3) based on the longer or shorter of the recommended interval R, and / or a4) based on the rule that takes into account at least one requirement, limitation or situation commonly present at the operating site (3), and a5) based on the rule applicable to the corresponding device (1), and b) performing at least one of the following: maintaining said device (1), cleaning said device (1) and replacing at least a portion of said device (1), and The procedure performed with respect to all devices (1) showing a ratio r comprised in said higher range III comprises at least one of the following steps: determining said updated calibration time interval A(t n ) as at least one of: c1) longer than said currently applied calibration time interval A(t n-1 ) and shorter than or equal to said recommended interval R determined for the respective device (1), c2) based on rules stating at least one requirement, limit or condition prevailing at said operating site (3), c3) equal to the longest interval or one of the longest intervals comprised in a set of predefined intervals comprising a limited number of intervals of different lengths shorter than or equal to said recommended interval R determined for the respective device (1), c4) shorter than or equal to at least one of: a maximum allowed interval length defined for the respective device (1) and a maximum allowed interval length defined for said operating site (3), and / or c5) based on said rules applicable to the respective device (1).

7. The method according to any one of claims 1 to 5, further comprising the step of: repeating the performance of said method for at least one further calibration period by: The method steps of performing the calibration, determining the ratio r, reviewing and updating the currently applied calibration time interval A(t n-1 ) and scheduling and performing the next calibration are performed during each cycle. wherein, during each cycle, following the first execution of the method, the calibration time interval A(t n-1 ) of the current application is given by the corresponding updated calibration time interval A(t n ) determined during the preceding cycle.

8. The method according to any one of claims 1 to 5, wherein: each recommendation interval R is determined such that the recommendation interval R determined for a device (1) showing a higher degree of compliance is longer than the recommendation interval R determined for a device (1) showing a lower degree of compliance and vice versa, each calibration of each device (1) arranged according to one of the schedules terminates at a calibration time t of the operating time interval OTI n is performed, the respective device (1) having been operated at the operating site (3) during the operating time interval OTI, and / or for each scheduled calibration time t determined for one of the devices (1) S corresponding to the respective scheduled calibration time t S with a length given by the time difference between the calibration time t n and the scheduled interval S. The scheduled interval S is determined for each scheduled calibration time t n for which the respective device (1) or, in case the device (1) has been replaced, its predecessor has been calibrated last. S before.

9. The method according to claim 8, further comprising the step of: For at least one or each calibration of at least one or all devices (1) of the group, a data set k is recorded immediately following the respective calibration, the data set k comprising a device identification d of the respective device (1) and at least two or all of the following: the recommended interval R, the currently applied calibration time interval A(t n-1 ), the updated calibration time interval A(t n ), the scheduled interval S and the operating time interval OTI, and performing at least one of the following: determining at least one indicator indicative of the performance of said method on the basis of at least one of said data sets k or on the basis of said intervals comprised in at least one of said data sets k, recording at least one of said indicators, displaying at least one of said indicators, monitoring at least one of said indicators and issuing a notification when one of the monitored indicators exceeds a threshold value defined for the corresponding indicator.

10. The method of claim 9, wherein, said indicators comprise at least one of the following: a first asset value V1(k) quantifying a cost associated with a calibration time interval A(t n-1 ) being shortened such that the updated calibration time interval A(t n ) is shorter than the recommended interval R, a second asset value V2(k) quantifying a risk associated with the current application's calibration time interval A(t n-1 ) being extended such that the updated calibration time interval A(t n ) is longer than the recommended interval R's update associated increased risk, a third asset value V3(k) quantifying a cost reduction potential of an updated use of the current application, wherein the third asset value V3(k) is quantified by a calibration time interval A(t n-1 ) being extended such that the updated calibration time interval A(t n ) is shorter than or equal to the recommended interval R, a fourth asset value V4(k) quantifying a risk reduction potential of an updated use of the current application A(t n-1 ) is reduced such that the updated calibration time interval A(t n ) is longer or equal to the recommended interval R, a combined asset value VC(k) given by only one of said first asset value VI(k), said second asset value V2(k), said third asset value V3(k) and said fourth asset value V4(k) defined for the corresponding data set k, at least one arranged asset value VS1(k), VS2(k), VS3(k), VS4(k), VCS(k), each arranged asset value being determined by replacing the updated calibration time interval A(t) applied in the respective determination by said arranged interval S n ) in the same way as one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and the combined asset value VC(k), at least one realized asset value VI1(k), VI2(k), VI3(k), VI4(k), VCI(k), each realized asset value being determined by replacing in the respective determination the updated calibration time interval A(t) by the operation time interval OTI n ) in the same way as one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and the combined asset value VC(k), at least one calibration value W(k), wherein each calibration value W(k) is determined based on or as a difference or an absolute value of the difference or a quotient of the operating time interval OTI and the scheduled calibration time interval S comprised in the respective data set k, based on the intervals comprised in one of the data sets k, based on or as a difference or an absolute value of the difference or a quotient of the recommended interval R and the currently applied calibration time interval A(t n-1 ) between the recommended interval R and the currently applied calibration time interval A(t n-1 ) based on at least one indicator value determined based on the interval included in one of the data sets k, Based on or as the recommended interval R and the updated calibration time interval A(t) n The difference between (t) and (t'), or the absolute value of the difference, or the recommended interval R and the updated calibration time interval A(t) n The quotient of ), and at least one index value determined based on the interval included in one of the datasets k. based on or as a difference between the updated calibration time interval A(t n ) and the scheduled interval S or an absolute value of the difference or a quotient of the updated calibration time interval A(t n ) and the scheduled interval S, at least one indicator value determined based on the interval included in one of the data sets k, based on or as a difference between the updated calibration time interval A(t n ) and the currently applied calibration time interval A(t n-1 ) or an absolute value of the difference or a quotient of the updated calibration time interval A(t n ) and the currently applied calibration time interval A(t n-1 ), at least one indicator value determined based on the interval included in one of the data sets k.

11. The method according to claim 10, further comprising the steps of: defining at least one device group, wherein the device groups comprise at least one of at least one device group each comprising a single specific device (1), at least one device group each comprising devices (1) of a given class or type, at least one device group each comprising devices (1) operating on a specific work section of the operating site (3) or on a work section that needs to be shut down each time one of the devices (1) operating on that work section is calibrated, a device group comprising all devices (1) operating on the operating site (3) and / or at least one other device group, determining at least one group indicator for each of at least one of the device groups, wherein each group indicator is determined based on an average value or an average value of absolute values of ones of the indicators determined for each of the data sets k recorded for the devices (1) comprised in the device group during a given time period Ati, and performing at least one of determining at least one of the group indicators for several consecutive given time periods Ati, recording at least one of the group indicators, displaying at least one of the group indicators, monitoring at least one of the group indicators and issuing a notification when one of the monitored group indicators exceeds a threshold value defined for the respective group indicator.

12. The method of claim 11, further comprising the step of: performing at least one of identifying, quantifying, providing, displaying and monitoring at least one of an increased risk, an increased cost, a risk reduction potential available for use or not for use according to the recommendation interval R and a cost reduction potential available for use or not for use according to the recommendation interval R based on at least one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k), the combined asset value VC(k), the scheduled asset value VS(k), the implemented asset value VI(k) and / or at least one of the group indicators determined based on one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k), the combined asset value VC(k), the scheduled asset value VS(k) or the implemented asset value VI(k).

13. The method of claim 12, further comprising the step of: determining at least one root cause of the threshold value being exceeded based on the indicators and / or the group indicators in case one of the increased risk, the increased cost, the cost reduction potential not for use and / or the risk reduction potential not for use exceeds a given threshold value.

14. The method according to claim 13, further comprising at least one of the following steps: identifying at least one of the increased risk, increased cost, unused cost reduction potential and / or unused risk reduction potential quantified based on at least one of the first asset value V1(k), the second asset value V2(k), the third asset value V3(k), the fourth asset value V4(k) and / or at least one of the group of indicators determined based on the first asset value V1(k), the second asset value V2(k), the third asset value V3(k) and / or the fourth asset value V4(k) as root cause when the corresponding value quantified based on at least one of the arranged asset values VS1(k), VS2(k), VS3(k), VS4(k) and / or at least one of the group of indicators determined based on the arranged asset values VS1(k), VS2(k), VS3(k), VS4(k) exceeds a predefined threshold value, identifying an arrangement as root cause when the increased risk, the increased cost, the unused risk reduction potential and / or the unused cost reduction potential quantified based on at least one of the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) and / or at least one of the group of indicators determined based on the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) exceeds a predefined threshold value compared to the corresponding characteristic quantified based on the arranged asset values VS1(k), VS2(k), VS3(k), VS4(k), and identifying the compliance of the executed calibrated arrangement to the schedule as root cause when the increased risk, the increased cost, the unused risk reduction potential and / or the unused cost reduction potential quantified based on at least one of the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) and / or at least one of the group of indicators determined based on the realized asset values VI1(k), VI2(k), VI3(k), VI4(k) exceeds a predefined threshold value compared to the corresponding characteristic quantified based on the arranged asset values VS1(k), VS2(k), VS3(k), VS4(k).

15. The method according to claim 14, further comprising at least one of the following steps: modifying the method by taking a corresponding countermeasure once a root cause has been identified, and modifying at least one of the following when a compliance arrangement has been identified as root cause: at least one of the rules predetermined for the ratio ranges I, II, III and at least one of the process steps of the process identified as root cause, the arrangement and / or the calibration execution process identified as root cause.

16. A calibration optimization system (17) designed to perform at least one of the method steps of the method according to any one of claims 9 to 15, wherein: the system (17) comprises: the system (17) comprises: a memory (15), an interface (21) designed to receive data required for the system (17) to store or determine and to store the data set k in the memory (15), a computing device (19) and a computer program SW implemented on the computing device (19) and causing the computing device (19) to perform the determination of an indicator and / or of a group of indicators based on the data set k stored in the memory (15), and wherein the system (17) is designed to perform at least one of: recording at least one of the indicators and / or of the group of indicators, providing at least one of the indicators and / or of the group of indicators via an output (25) of the system (17), displaying at least one of the indicators and / or of the group of indicators on a display (23) comprised in or connected to the system (17), monitoring at least one of the indicators and / or of the group of indicators, and issuing a notification when one of the monitored indicators and / or of the monitored group of indicators exceeds a threshold value defined therefor.

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