Methods for monitoring the power consumption of a measuring point, as well as measuring point and process control system

Abstract

The invention relates to a method for monitoring the power consumption of a measuring point (1) with a two-wire configuration, comprising the following steps: - Providing a measuring point (1) with a transmitter (10) and a sensor (20), wherein the transmitter (10) has a loop input (11) and a loop output (12) which are connected via a current loop (13) to a control station (30) for power and data transmission, wherein the transmitter (10) is connected to the sensor (20) for power and data transmission, - Determining a sensor measurement value (MW) by the sensor (20), - Output of a transmission current (TS) dependent on the sensor measurement value (MW) at the loop output (12) by the transmitter (10), - Determining a supply voltage (VS) provided by the control center (30) between the loop input (11) and the loop output (12) of the transmitter (10), - Determining a supply power (VL) based on the supply voltage (VS) and the transmission current (ÜS), - Determining the power consumption (BL) of the transmitter (10), - Comparing the consumption power (BL) with the supply power (VL), - Outputting comparison-dependent user information (BI).

Description

[0001] The invention relates to a method for monitoring the power consumption of a measuring point, as well as to a measuring point and a process control system.

[0002] In analytical measurement technology, particularly in water management, environmental analysis, industrial applications such as food technology, biotechnology, and pharmaceuticals, as well as for a wide variety of laboratory applications, measured variables such as pH, conductivity, or the concentration of analytes, such as ions or dissolved gases in a gaseous or liquid medium, are of great importance. These measured variables can be recorded and / or monitored using electrochemical sensors, such as optical, potentiometric, amperometric, voltammetric, or coulometric sensors, or even conductivity sensors.

[0003] The measured values ​​determined by the sensors are processed in so-called measuring transducers. One challenge here, which arises particularly in potentially explosive environments, is that only a limited amount of energy can be made available to the measuring transducer. Two-wire field devices are often used, especially in potentially explosive areas. For historical reasons, such two-wire field devices are predominantly designed so that a supply current of between 4 mA and 20 mA (= milliamperes) flowing in the single wire pair formed as a current loop simultaneously represents the measured value currently generated by the field device or the measuring point, or the setting value currently sent to the field device.Consequently, a particular problem with such two-wire field devices is that the electrical power that can be, or is to be, converted by the field device electronics – referred to below as "available power" – can fluctuate over a wide range during operation. To take this into account, modern two-wire field devices (2L field devices), especially modern two-wire measuring devices (2L measuring devices) with a (4 mA to 20 mA) current loop, are typically designed such that their device functionality, implemented by a microcomputer incorporated in the evaluation and operating circuit, is limited to what can be performed at a minimum current value. Some devices also operate in such a way that energy-intensive operations of the microcontroller are repeatedly interrupted until a connected energy storage device (e.g., a capacitor) is sufficiently filled to continue the operation.

[0004] It is therefore an object of the invention to propose a method which facilitates the operation of a field device with fluctuating available power.

[0005] This object is achieved according to the invention by a method for monitoring a power consumption of a measuring point with a two-wire structure according to claim 1.

[0006] The method according to the invention comprises the following steps: - Providing a measuring point with a measuring transducer and a sensor, wherein the measuring transducer has a loop input and a loop output, which are connected via a current loop to a control center for energy and data transmission, wherein the measuring transducer is connected to the sensor for energy and data transmission, - Determination of a sensor measurement value by the sensor, - Output of a transmission current at the loop output by the transmitter, which depends on the sensor measured value, - Determination of a supply voltage provided by the control center between the loop input and the loop output of the measuring transducer, - Determining a supply power based on the supply voltage and the transmission current, - Determining the power consumption of the measuring transducer, - comparing consumption power with supply power, - Output user information depending on the comparison.

[0007] The method according to the invention enables the power consumption of a measuring point to be monitored and made available to the user. This allows energy-intensive activities to be carried out at an optimal time without disrupting the measuring point's normal measuring operation. Furthermore, the user can see the current available supply power or consumption power at a glance.

[0008] According to one embodiment of the invention, the user information is output at the measuring transducer and / or after transmission of the user information to the control center at the control center via an output unit.

[0009] According to a further embodiment of the invention, the comparison checks whether the supply power is sufficient for additional activity of the measuring transducer, wherein the user information contains the result of the check.

[0010] According to one embodiment of the invention, in the step of outputting a transmission current dependent on the sensor measured value, a mathematical mapping is used to determine the transmission current to be output. If the supply power is insufficient for an additional activity, the user information includes a suggestion for power optimization. The power optimization includes adjusting the mathematical mapping so that a higher transmission current is output for the sensor measured value than before the mathematical mapping was adjusted. If the maximum transmission current ÜS may be 20 mA, for example, in an explosion-proof area, this upper current limit is naturally taken into account during the adjustment.

[0011] According to one embodiment of the invention, the method further performs a step of data processing in the transmitter and / or wireless communication via a communication module when the supply power is sufficient for an additional activity.

[0012] According to one embodiment of the invention, a temporal development of an excess power based on the comparison is stored and analyzed in the measuring transducer.

[0013] According to one embodiment of the invention, in the case of a cyclical temporal development of the surplus power, the user information indicates, based on the analysis, a power time window in which the surplus power is sufficient for certain operations of the measuring transducer.

[0014] According to one embodiment of the invention, the results of the analysis of the temporal development of the excess power are used to determine a time for an automatic start of certain operations of the measuring transducer.

[0015] The object described above is also achieved by a measuring point according to claim 9.

[0016] The measuring point according to the invention comprises: - a measuring transducer with a loop input and a loop output, wherein the loop input and the loop output are suitable for being connected via a current loop to a control center for energy and data transmission, - a sensor connected to the transmitter for energy and data transmission, wherein the measuring point is suitable for carrying out the method according to the invention.

[0017] The object described above is also achieved by a process control system according to claim 10.

[0018] The process control system according to the invention comprises: - a measuring point according to the invention, - a control center which is connected to the measuring point for energy and data transmission, wherein the measuring transducer and / or the control center has a display unit.

[0019] The invention is explained in more detail with reference to the following description of the figures. They show: - Fig. 1: a schematic representation of a process control system according to the invention.

[0020] The Fig. The process control system 100 according to the invention, shown in Figure 1, comprises a measuring point 1 and a control center 30. The measuring point 1 is connected to the control center 30 for energy and data transmission. The measuring point 1 and / or the control center 30 has a display unit 40. The output unit 40 is, for example, a display or another user interface. The control center 30 has a DC voltage source, which is Fig. 1 with U IN The DC voltage source is preferably adjustable in voltage.

[0021] The measuring point 1 comprises a measuring transducer 10 and a sensor 20 or a device that combines both functionalities. The measuring transducer 10 has a loop input 11 and a loop output 12, wherein the loop input 11 and the loop output 12 are suitable for being connected to a control center 30 for energy and data transmission via a current loop 13. The sensor 20 is connected to the measuring transducer 10 for energy and data transmission. The measuring point 1 is a field device or a combination of field devices in which energy and data transmission are transmitted via one and the same interface. Preferably, the measuring transducer 10 or the measuring point 1 is a two-wire field device.

[0022] The following describes the inventive method for monitoring the power consumption of a measuring point 1.

[0023] A first step involves providing the measuring point 1 described above. The measuring transducer 10 is connected to the control center 30 via the current loop 13 for power and data transmission. The current loop 13 preferably allows a current flow of 4 mA to 20 mA.

[0024] In the next step, a sensor measurement value MW is determined by the sensor 20. In Fig. 1, the sensor measured value MW is also known as x MEASDepending on the type of sensor 20, the sensor measured value MW is, for example, a voltage (e.g., with a pH sensor) or a resistance value (e.g., with a temperature sensor). The measuring transducer 10 processes the sensor measured value MW so that the sensor measured value MW is transformed into a transmission current ÜS. The transmission current ÜS is between 4 mA and 20 mA. The transmission current ÜS is directly dependent on the sensor measured value MW. Preferably, the transmission current ÜS is proportional to the sensor measured value MW. The current transmission current ÜS, the temporal development of the transmission current ÜS and / or the current sensor measured value MW or the temporal development of the sensor measured value MW are preferably stored in a memory of the measuring transducer 10.

[0025] The next step is to output the transfer current ÜS at loop output 12 via the measuring transducer 10. Because the transfer current ÜS is dependent on the sensor measured value MW, the transfer current ÜS directly reflects the sensor measured value MW. This allows the control center 30 to directly deduce the sensor measured value MW from the transfer current ÜS. The transfer current ÜS preferably does not exceed 20 mA to ensure its use in potentially explosive atmospheres.

[0026] In a further step, a supply voltage VS provided by the control center 30 between the loop input 11 and the loop output 12 of the measuring transducer 10 is determined. The supply voltage VS is preferably equal to the voltage supplied by the DC voltage source U INHowever, in an embodiment not shown, the current loop 13 has further consumers, so that the supply voltage VS is lower than that supplied by the DC voltage source U IN The measuring transducer 10 stores the current supply voltage VS and its temporal development, preferably in the memory.

[0027] The next step is to determine a supply power VL based on the supply voltage VS and the transmission current ÜS. To do this, the measuring transducer 10 multiplies the current supply voltage VS by the current transmission current ÜS. The current supply power VL and the temporal development of the supply power VL are preferably stored by the measuring transducer 10.

[0028] In a subsequent step, a power consumption BL of the measuring transducer 10 is determined. The power consumption BL is the electrical power required by the measuring transducer 10. This includes, for example, the electrical energy required by the sensor 20 for operation or the electrical energy required by the measuring transducer 10 to operate the internal control modules such as the microprocessor or output units 40, such as status LEDs, displays, loudspeakers, data communication via communication module 14, etc. The communication module 14 is suitable for communicating with a communication station 50.

[0029] Then, a step of comparing the consumption power BL with the supply power VL takes place. Here, an excess power ÜL is preferably determined, i.e. a difference between the supply power VL and the consumption power BL. Since the supply power VL depends directly on the transmission current ÜS, which in turn depends on the sensor measured value MW, it can happen under certain measuring conditions that only a low sensor measured value MW is measured by sensor 20. This consequently leads, with a proportional mapping of the sensor measured value MW to the transmission current ÜS, to a low transmission current ÜS and thus to a low supply power VL. In such cases, the excess power ÜL is only small, which in Fig. 1 is marked with ÜL1. In the opposite case, i.e. if there is a high sensor reading MW and thus a high transmission current ÜS and a high supply power VL, the excess power ÜL will be equally high, which in Fig. 1 is marked by ÜL2. Fig. Figure 1 also shows a graph showing the surplus power (ÜL), i.e., the development of the surplus power (ÜL) over time. The graph thus indirectly also shows the temporal development of the supply power (VL) and the consumption power (BL). Of course, it is possible to display the supply power (VL) and consumption power (BL) or their temporal development in addition to the surplus power (ÜL).

[0030] According to one embodiment, the comparison checks whether the supply power VL is sufficient for an additional activity of the measuring transducer 10. For this purpose, the corresponding power requirements for each additional activity are stored in the measuring transducer 10. This means that the measuring transducer 10 knows, for example, the additional power consumption of the communication module 14.

[0031] Furthermore, a step of outputting user information BI dependent on the comparison is carried out. The user information BI is output at the measuring transducer 10 and / or after transmission of the user information BI to the control center 30 at the control center 30, by means of the output unit 40. As in Fig. 1, the current surplus power ÜL, ÜL1, ÜL2 is output on a display on the measuring transducer 10. Of course, it is also possible to output the current consumption power BL and / or the current supply power VL separately or simultaneously. For example, a speedometer display is used for the output (see Fig. 1). It is of course also possible to display the temporal development of the surplus power ÜL and / or the supply power VL and / or the consumption power BL, for example by means of a diagram (see Fig. 1). Preferably, in addition to displaying the user information BI, a signal color is used, for example, which allows the user to more quickly recognize whether the supply power VL is sufficient (signal color green), critical (signal color orange), or too low (signal color red) to start or delay energy-hungry activities, such as wireless data transmission via communication module 14, in the measuring transducer 10.

[0032] When the test described above is performed, the test result is preferably output with user information BI. In particular, for example, if the user requests data transmission via communication module 14, but the supply power VL is insufficient, an error message or warning with / without recommended action is output with user information BI.

[0033] Preferably, in the step of outputting a transmission current ÜS dependent on the sensor measured value MW, a mathematical mapping is used to determine the transmission current ÜS to be output. In this case, if the supply power VL is not sufficient for an additional activity, the user information BI includes a suggestion for power optimization. The power optimization comprises adjusting the mathematical mapping so that a higher transmission current US is output for the sensor measured value MW than before the mathematical mapping was adjusted.

[0034] Wherein, if the supply power VL is sufficient for an additional activity, the method further carries out a step of data processing in the measuring transducer 10 and / or wireless communication via a communication module 14.

[0035] According to one embodiment of the method, a temporal development of the excess power ÜL is stored and analyzed in the measuring transducer 10. In particular, it is checked whether recurring, e.g., time-of-day-dependent, curves of the excess power ÜL exist. If such cyclical temporal developments of the excess power ÜL exist, a power time window ZF is output with the user information BI, in which the excess power ÜL is large enough to perform certain operations (see Fig.1). This power time window ZF is ideal for additional activities or operations of the measuring transducer 10. "Cyclically" here means that a development of the excess power (ÜL) is estimated. For example, the recorded development of the excess power (ÜL) is evaluated by "artificial intelligence," and the future development is estimated. This makes it possible, for example, to identify patterns in the development of the excess power (ÜL).

[0036] Preferably, the results of the analysis, in particular the identified power time windows ZF, of the temporal development of the excess power ÜL are used to determine a time for an automatic start of certain activities or operations of the measuring transducer 10. In particular, firmware updates and the exchange of larger data volumes, for example, via the communication module 14 and the communication station 50, can be transmitted conveniently and securely. List of reference symbols 1 measuring point 10 transmitters 11 Loop input 12 Loop output 13 current loop 14 Communication module 20 sensors 30 Control Center 40 output unit 50 communication stations 100 Process control system MW sensor reading Overcurrent transmission current ÜL, ÜL1, ÜL2 surplus power VS supply voltage VL pension benefit BL consumption performance BI user information ZF performance time window

Claims

[1] Method for monitoring the power consumption of a measuring point (1) with a two-wire structure, comprising the following steps: - Providing a measuring point (1) with a measuring transducer (10) and a sensor (20), wherein the measuring transducer (10) has a loop input (11) and a loop output (12) which are connected via a current loop (13) to a control center (30) for energy and data transmission, wherein the measuring transducer (10) is connected to the sensor (20) for energy and data transmission, - Determination of a sensor measured value (MW) by the sensor (20), - Output of a transmission current (ÜS) dependent on the sensor measured value (MW) at the loop output (12) by the measuring transducer (10), - Determining a supply voltage (VS) provided by the control center (30) between the loop input (11) and the loop output (12) of the measuring transducer (10), - Determination of a supply power (VL) based on the supply voltage (VS) and the transmission current (ÜS), - Determining a consumption power (BL) of the measuring transducer (10), - comparing the consumption power (BL) with the supply power (VL), - Output of user information (BI) dependent on the comparison. [2] Method according to claim 1, wherein the output of the user information (BI) at the measuring transducer (10), and / or after transmission of the user information (BI) to the control center (30) at the control center (30), takes place via an output unit (40). [3] Method according to one of the preceding claims, wherein the comparison checks whether the supply power (VL) is sufficient for an additional activity of the measuring transducer (10), wherein the user information (BI) contains the result of the check. [4] Method according to claim 3, wherein, in the step of outputting a transmission current (ÜS) dependent on the sensor measured value (MW), a mathematical mapping is used to determine the transmission current (ÜS) to be output, where, if the supply power (VL) is not sufficient for an additional activity, the user information (BI) includes a proposal for performance optimization, wherein the performance optimization comprises an adjustment of the mathematical mapping so that a higher transmission current (US) is output for the sensor measured value (MW) than before the adjustment of the mathematical mapping. [5] Method according to claim 3, wherein, when the supply power (VL) is sufficient for an additional activity, the method further carries out a step of data processing in the transmitter (10) and / or wireless communication via a communication module (14). [6] Method according to one of the preceding claims, wherein a temporal development of an excess power (ÜL) based on the comparison is stored and analyzed in the measuring transducer (10). [7] Method according to claim 6, wherein the user information (BI) indicates, in the case of a cyclical temporal development of the excess power (ÜL), based on the analysis, a power time window (ZF) in which the excess power (ÜL) is sufficient for certain operations of the measuring transducer (10). [8] Method according to claim 6 or 7, wherein the results of the analysis of the temporal development of the excess power (ÜL) are used to determine a time for an automatic start of certain operations of the measuring transducer (10). [9] Measuring point (1) comprising, - a measuring transducer (10) with a loop input (11) and a loop output (12), wherein the loop input (11) and the loop output (12) are suitable for being connected via a current loop (13) to a control center (30) for energy and data transmission, - a sensor (20) which is connected to the measuring transducer (10) for energy and data transmission, wherein the measuring point (1) is suitable for carrying out the method according to one of the preceding claims. [10] Process control system (100), comprising, - a measuring point (1) according to claim 9, - a control center (30) which is connected to the measuring point (1) for energy and data transmission, wherein the measuring transducer (10) and / or the control center (30) has a display unit (40).

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