Method and device for determining the electrical resistance of a standard loop

Abstract

The invention relates to a method for determining the resistance of a standard loop (10) for a loop electrical conductivity measuring apparatus. The standard loop comprises an electrically conductive closed loop. The loop is connected in an electrical circuit to a first connection point on the loop and to a second connection point on the standard loop, the first and second connection points defining a first electrical circuit portion (B1) on the standard loop and a second electrical circuit portion (B2) on the standard loop.The method comprises the steps of measuring a current which flows respectively in the first and second electrical circuit portions of the standard loop when an electrical current passes in parallel in the first and second electrical circuit portions and determining the total resistance of the standard loop as a function of the electrical current measured in the first and second electrical circuit portions of the standard loop.

Description

Title of the invention: Method and device for determining the electrical resistance of a standard loop Technical field

[0001] The present invention relates to a method for determining the electrical resistance of a standard loop. The standard loop being, in particular, suitable for use in calibrating devices for measuring the electrical conductivity of a loop in an electrically conductive network. Prior art

[0002] Apparatuses for measuring an electrical conductivity of a loop in an electrically conductive network, the loop being a metal loop formed by a succession of metallic elements constituting the electrically conductive network, by means of a coupling clamp to the loop are known. Methods for calibrating this type of apparatus generally comprise the provision of a calibration device, and the calibration of the measuring apparatus is carried out by taking into account the known characteristics of the calibration device. This procedure aims to verify the accuracy and repeatability of the measurement of the characteristics of the conductive network by the measuring apparatus. Improving the reliability of the calibration procedures for these devices would be advantageous. Summary of the invention

[0003] The present invention provides a method, a controller, a system and a device for determining the electrical resistance of a standard loop, the standard loop being suitable for use in calibrating devices for measuring an electrical conductivity of a loop in an electrically conductive network. Furthermore, the invention relates to a kit for calibrating a measuring device to improve the calibration procedure. The invention allows in particular, the determination of the resistance of a loop without having to detach two ends of the loop to determine its resistance by using a current flowing in the loop unidirectionally. The invention implements a measuring method which uses a current flowing in parallel in two parts of an electrical circuit included in the loop.

[0004] According to one aspect, the invention relates to a method for determining the resistance of a standard loop, comprising one or more of the following characteristics: • the standard loop is suitable for use in calibrating a loop electrical conductivity measuring device, • the standard loop comprises an electrically conductive closed loop, • the standard loop is connected to an electrical circuit at a first connection point on the standard loop and at a second connection point on the standard loop, • the first and second connection points defining at least a first portion of electrical circuit on the standard loop, and optionally a second portion of electrical circuit on the standard loop, • the method comprising at least one of the steps of: • measurement of an electric current which flows in at least one of the first and second electrical circuit portions of the standard loop when an electric current passes, optionally in parallel, in at least one of the first and second electrical circuit portions; • determination of the total resistance of the standard loop as a function of the electric current measured in at least one of the first and second portions of the electric circuit of the standard loop.

[0005] The first electrical circuit portion and the second electrical circuit portion may have substantially similar electrical resistance values. In some examples, these electrical resistances may differ by less than one-third, or less than one-quarter, or less than one-eighth, or less than one-tenth, or less than one-twentieth, of the greater resistance of the two portions.

[0006] The electric current, in at least one of the first electrical circuit portion and the second electrical circuit portion, may be measured by a current loop.

[0007] The electric current flowing in at least one of the first and second electrical circuit portions may be generated by electrical power supply means.

[0008] Determining the total resistance of the standard loop may include adding a first resistance value indicating the resistance of the first electrical circuit portion and a second resistance value indicating the resistance of the second electrical circuit portion.

[0009] Determining the total resistance of the standard loop may include adding a first current value indicating an electrical current measured in the first electrical circuit portion and a second current value indicating an electrical current measured in the second electrical circuit portion.

[0010] Determining the total resistance of the standard loop may comprise dividing the sum of the values ​​of the electric currents measured respectively in the first portion of the electric circuit and the second portion of the electric circuit by the product of the values ​​of the electric currents measured respectively in the first portion of the electric circuit and the second portion of the electric circuit.

[0011] The step of measuring the current flowing in the first and second electrical portions of the standard loop can be repeated to obtain a plurality of measured electrical current values.

[0012] Obtaining a plurality of measured electrical current values ​​may include applying a plurality of different voltages to obtain different measured electrical current values ​​in the standard loop.

[0013] The method may further comprise a preliminary step of: • connection of the standard loop in the electrical circuit at the first connection point on the standard loop and at the second connection point on the standard loop.

[0014] According to one aspect, the invention relates to a controller for determining the resistance of a standard loop, the standard loop being optionally suitable for use in calibrating a loop electrical conductivity measuring apparatus, the standard loop comprising an electrically conductive closed loop. The controller may be configured to implement one or more of the following steps: • emit a control signal to apply electrical power to a standard loop; • receive a first input signal indicating an electric current flowing in a first portion of the electrical circuit of the standard loop; • receive a second input signal indicating an electric current flowing in a second portion of the electrical circuit of the standard loop; • calculate, on the basis of the first and second input signals, the total resistance of the standard loop.

[0015] The controller may be configured to add a first value indicating the resistance of the first electrical circuit portion to a second value indicating the resistance of the second electrical circuit portion to determine the total resistance of the standard loop.

[0016] The controller can be configured to: • divide : • the sum of the values ​​indicating the respective resistances of the first portion of the electrical circuit and the second portion of the electrical circuit, • by : • the product of the values ​​indicating the respective resistances of the first portion of the electrical circuit and the second portion of the electrical circuit, • to determine the total resistance of the standard loop.

[0017] According to one aspect, the invention relates to a system for determining the electrical resistance of a standard loop, the standard loop comprising an electrically conductive closed loop, the system comprising one or more of the following features: • a first electrical connection means for being connected to a first connection point on the standard loop; • a second electrical connection means for being connected to a second connection point on the standard loop, the first connection point on the standard loop and the second connection point on the standard loop defining a first electrical circuit portion of the standard loop and a second electrical circuit portion of the standard loop; • electrical power supply means electrically connected to the first and second electrical connection means; • first current measuring means for measuring an electric current in the first portion of the standard loop; • second current measuring means for measuring an electric current in the second portion of the standard loop.

[0018] The means for supplying electrical power may comprise a current generator, optionally a stabilized current generator.

[0019] At least one of the first and second current measuring means may comprise a current loop.

[0020] The system may include a controller as described in the present disclosure.

[0021] According to one aspect, the invention relates to a kit for calibrating a measuring device, the measuring device being configured to induce an electric current in a loop by means of a clamp and obtain the value of the current flowing in the loop, the kit comprising: • a standard loop comprising an electrically conductive closed loop; • a system for determining electrical resistance according to the present disclosure.

[0022] The standard loop may be a metal loop, with an electrical resistance of at most 10 milliOhms, and preferably at most 1 milliOhms. The standard loop may be a copper loop.

[0023] The standard loop may be a closed loop, optionally provided with a mechanical connection and not welded, to connect the two ends of the loop.

[0024] The kit may further comprise a list of instructions which, when implemented, results in the execution of the steps of the method according to the present disclosure.

[0025] The instruction list may be implemented by a computer controller, to configure a controller as described in the present disclosure.

[0026] The kit may further comprise a controller as described in the present disclosure.

[0027] According to one aspect, the invention relates to a device for determining the electrical resistance of a standard loop, comprising a system according to the present disclosure, and a controller according to the present disclosure. List of Figures

[0028] We will now describe examples of embodiments of the present invention with reference to the appended figures where the same references designate from one figure to another identical or functionally similar elements:

[0029] [Fig.l] is a schematic representation of a measuring device capable of implementing a method for controlling a clamp coupled to a device.

[0030] [Fig.2] is a diagram of an example of means for determining the resistance of a standard loop; and

[0031] [Fig.3] is a diagram illustrating the steps of the process. Detailed description of the invention

[0032] The invention relates to the determination of the resistance of a standard loop 1, said standard loop 1 being capable of facilitating the calibration of a loop electrical conductivity measuring apparatus 5. The measuring apparatus 5 is configured to induce an electric current in a loop by means of a clamp 52, and to obtain the value of the current flowing in a loop 6, in particular a metal loop, of an electrically conductive network, so as to determine the electrical conductivity of said loop. An example of a relevant measuring apparatus is described in French patent no. FR 3 091 760 B, but it may be useful to determine the resistance of a standard loop for other examples of devices.

[0033] [Fig.l] is a schematic representation of such a measuring device 5 capable of measuring the conductivity of a loop 6, or controlling an electrical circuit. This control can be implemented in a ship or an aircraft, for example, or in any other electrical circuit, to check its integrity and its electrical resistance. To ensure the accuracy of such a device, it is necessary to calibrate it with a standard loop whose resistance is known. The invention relates to a method, a controller, a system and a device for determining the resistance of such a standard loop to enable the calibration of a measuring device 5.

[0034] The measuring device 5 is connected to a removable clamp 52 which grips one of the metal elements belonging to the loop 6 which is the subject of an electrical continuity measurement. The clamp 52 is connected to a power supply generator 51 delivering an electric current which is transmitted by electromagnetic induction from the clamp 52 to the loop (current C1), when the clamp 52 surrounds an element of the loop 6. The same clamp 52 collects the electric current C2 circulating in the loop 6 by electromagnetic induction, which allows the measuring device 5 to determine the value of the electrical resistance of the loop 6 representative of the electrical continuity of the latter.

[0035] The clamp 52 comprises: an electrical circuit 520, such as a coil consisting of a winding of conductive wire, configured to inject the current C1 into the loop 6 and to measure the intensity of the current C2 flowing in this same loop 6; a storage memory 521 capable of storing in particular identification data (or an identifier) ​​of the clamp 52, and a Hall effect sensor (not referenced) which makes it possible to verify that the clamp is properly closed (if the sensor detects that the clamp is open, all measurements are stopped).

[0036] According to a particular example, the storage memory 521 of the clamp 52 stores, in addition to the identifier of the clamp, at least one or more of the following quantities: an intensity value of a first test called the reference test, the phase shift value of the first test called the reference test between the calibration current injected into said clamp and the current collected by the clamp during this calibration, the number of turns of the clamp, the coefficient of the cable of the clamp. Some of these quantities make it possible to calculate an “offset” when a subsequent measurement is carried out on a loop using said clamp 52. It should be noted that the calculation of the “offset” is optional and depends on the level of precision sought in the measurement of the electrical continuity of the conductor or circuit measured.

[0037] The first test or calibration of the clamp 52 is carried out before its marketing, at the time of its manufacture for example, by supplying the clamp 52 with a reference electrical signal so as to obtain at least one reference intensity value (of an electrical signal) and / or the reference phase shift value. These values ​​are preferably recorded in the storage memory 521, but can also be stored in a memory of the device 5 or on a remote server.

[0038] Furthermore, the measuring device 5 comprises: means 53 for reading the identification data, the reference intensity value and the reference phase shift value, of the clamp 52 stored in the storage memory 521 of the latter, a processing unit, taking the form of a microprocessor 54, configured to calculate, on the basis of the measurements carried out by the clamp 52, the value of the resistance of the loop 6 representative of its electrical conductivity and possibly to determine possible wear of the clamp 52, for example at each use of the latter, after a predetermined number of uses or when the user wishes; a storage memory 55 comprising a database associating unique identification data (identifiers) of one or more clamps with a history of measurements carried out (current and / or frequency) during tests of said clamps which may occur at each use of the latter, after a predetermined number of uses or when the user voluntarily wishes to carry out a test of the clamp which he is using. The database may include a wear indicator (taking the form of a bit which can take a value “0” or “1”) associated with the identifier of each clamp.

[0039] Such a measuring device is thus configured to be able to carry out the control of the clamp which is coupled to it, in addition to the calculation of loop resistance and measurement of electrical conductivity.

[0040] As illustrated, the measuring device 5 makes it possible to measure the resistance of the loop 6, formed by the metal elements joined at points A, B, C and D, by placing the clamp 52 on the periphery of one of the metal elements belonging to this loop, namely the metal element 51 in this example.

[0041] As described above, a first test or calibration of the clamp 52 is carried out before it is marketed, at the time of its manufacture for example, by supplying the clamp 52 with a reference electrical signal so as to obtain at least one reference intensity value (of an electrical signal) and / or the reference phase shift value. This first test is carried out using a standard loop, at least the resistance of which is known.

[0042] The method, devices and system subject to the present disclosure aim to enable at least the determination of the resistance of such a standard loop.

[0043] Known methods for measuring the resistance of a standard loop involve creating a detachment point in the standard loop so that the two ends of the standard loop can be detached from each other to transform the standard loop into a unidirectional electrical conductor. In a second step, the resistance of the conductor from which the standard loop is formed is measured by flowing an electrical current from one end to the other, unidirectionally, the current flowing along the standard loop. Then, the two ends of the standard loop are reattached to reform the standard loop. The inventor realized that this way of measuring the resistance of a standard loop includes disadvantages, especially in that the method does not take into account the resistance of the connection between the two ends of the standard loop.

[0044] The invention relates to a more advantageous method, in which the resistance is measured while leaving the standard loop complete, in other words, without interrupting the conductivity of its electrical circuit. The new process takes into account several laws: • Law of nodes: The sum of the intensities of the currents entering through a node is equal to the sum of the intensities of the currents leaving the same node. • Law of meshes: In any mesh of a network, in the approximation of quasi-stationary regimes and provided that the variations in magnetic flux through the mesh are negligible, the algebraic sum of the potential differences along the mesh is constantly zero. • Ohm’s Law: • U = R x I; where • I = the intensity of the current flowing through the resistance; • R = the value of the resistance;

[0045] [Fig. 2] is a schematic representation of a system comprising means for implementing the new method. These means and the method will be described in parallel with reference to [Fig. 2].

[0046] The system is adapted to implement the method of determining the resistance of a standard loop, the standard loop being suitable for use in calibrating a loop electrical conductivity measuring apparatus, as disclosed in the present disclosure. The system comprises several components for implementing the method. The components are suitable for respectively implementing a part of the method and each component may have an advantage in combination with, or in the absence of, certain other components of the disclosed system.

[0047] The system and its components are intended to determine the resistance of a standard loop 10. The standard loop 10 may be an electrically conductive closed loop. The loop may be closed and welded or may have ends connected by a mechanical connection. Regardless of its form, the inventor has determined that it is advantageous to be able to determine the resistance of the standard loop without changing its shape or construction. This represents an advantage over methods of measuring standard loop resistance according to the prior art, where the standard loop has been opened to measure its total resistance. A disadvantage of these known methods is that the resistance of the connection between the two ends of the standard loop once connected to form a closed loop is not known and may influence the actual resistance of the standard loop.

[0048] The system comprises first and second electrical connection means 101 and 102, also called electrical connectors, for establishing an electrical connection between the standard loop 10 and electrical power supply means G. The electrical connection means may be an electrical and mechanical connection, for example an electrical clamp, a mount in which the ring of the standard loop is received to hold it and to electrically connect it, or any other form of electrical and / or mechanical connection making it possible to establish an electrical connection between the ring of the standard loop and the electrical power supply means G. The electrical power supply means G are in particular an electrical power source.

[0049] The electrical connection means 101 and 102 are connected by a first electrical conductor 141 and a second electrical conductor 142 to the electrical power source G. These conductors can take any suitable form for circulating the electrical current from the electrical power source G to the electrical connectors 101 and 102.

[0050] It is also advantageous to be able to measure the electrical potential difference, or voltage, between the electrical connectors 101 and 102. This allows the voltage drop across the standard loop 10 to be measured. Accordingly, a voltage detector V may be connected so as to allow the voltage across the standard loop 10 to be measured. The connection may be made either via the electrical connectors 101 and 102, or by passing through the electrical conductors 141 and 142, or by connecting directly to the standard loop 10 at or near the electrical connectors 101 and 102. Generally, the voltage detector V is connected by any means suitable for measuring the electrical potential drop across the standard loop 10.

[0051] The measurement of a current flowing in the standard loop 10 is carried out by current measuring means II and 12. The current measuring means II and 12 can be carried out by a current loop. In the illustrated configuration, this measurement is carried out by the current measuring rings 111 and 112. A first current measuring means 111 is arranged to measure an electric current in a first portion B1 of the standard loop 10. A second current detection means 112 is arranged to measure an electric current in a second portion B2 of the standard loop 10.

[0052] As shown in [Fig.2], the electrical connectors 101 and 102 are connected to the standard loop 10 at a first and a second connection point on the standard loop respectively such that the standard loop is divided into two separate electrical circuit portions B1 and B2. When an electrical current is applied between the electrical connectors 101 and 102 to flow in the standard loop 10, a portion of the current flows in parallel in the first electrical circuit portion B1 of the standard loop, while a second part of the current flows in parallel in the second portion of electrical circuit B2 of the standard loop.

[0053] The system being suitably arranged to supply a current to the separate electrical circuit portions B1 and B2 of the standard loop 10 and to measure the currents in these portions, the overall resistance of the standard loop can be determined as follows.

[0054] The electrical power source G supplies an electrical current, which is preferably a stabilized electrical current, to the standard loop 10. The electrical current flowing through each portion of the standard loop, B1 and B2, is measured by the current measuring means II and 12, which may be in the form of current loops, electrical coils connected to a multimeter to provide a simple output of a digital or analog value or signal representing a detected current. They may also be more sophisticated devices that perform an automated measurement and calculation of the actual current in amperes and output a value representing the current in amperes or other suitable units.

[0055] According to a particular embodiment, the measurement of the current flowing in the first and second electrical portions of the standard loop is repeated to obtain a plurality of measured electrical current values. In particular, obtaining a plurality of measured electrical current values ​​comprises applying a plurality of different voltages to obtain different measured electrical current values ​​in the standard loop.

[0056] While the electrical current flows in the standard loop 10, the voltage drop across the standard loop 10 is also detected using the voltage detection means V. The voltage detection means V may be a simple multimeter delivering a digital or analog value or signal representing a voltage differential detected between the two adjacent connection points at the electrical connectors 101 and 102. It may also be a more sophisticated device which performs an automated measurement and calculation of the voltage drop and outputs a value representing the voltage in volts or other suitable units.

[0057] Given the equations expressed above, it can be determined that the overall current flowing through the two standard loop electrical circuit portions B1 and B2 will be the same as the overall current generated by the electrical power source G. The electrical resistance of each standard loop electrical circuit portion B1 and B2 can be calculated based on the known voltage drop between the connection points of the electrical connectors and the known electrical current flowing through each standard loop electrical circuit portion B1 and B2.

[0058] Expressing the properties according to the fundamental equations relating to voltage, current and resistance:

[0059]

[0060]

[0061] • U is the voltage drop across the connection points on the standard loop 10. • R is the total resistance of the standard loop 10 • I is the total current supplied to the standard loop 10 • It is the total current measured in a first portion of the electrical circuit of standard loop B1 • 12 is the total current measured in a second portion of the circuit B2 standard loop electric • RI is the resistance of the first portion of the standard loop electrical circuit B1 • R2 is the resistance of the second portion of the standard loop electrical circuit B2 • U = R * I • R = U / I • R = RI + R2 • R = U / Il + U / I2 By rearranging the equations, we obtain the total resistance of the standard loop: / 1 + / 2 R —U* „- / 1 * / 2 It will also be appreciated that an alternative calculation can be made by first calculating RI as U / Il; calculating R2 as U / I2 and adding RI to R2 to find the total resistance R of the standard loop 10. The system of [Fig. 2] may further include a controller K that may include one or more of the following components: a processor 151, a storage memory 152, and one or more input / output modules 153, which may be configured to receive signals from various components of the system described herein. The controller K may be configured to communicate input values ​​between the processor 151, the memory 152, and the input / output modules 153 to perform certain calculations on the inputs and output the results. The controller K may include outputs to communicate the output parameters to a display D, which may display the output parameters or values ​​to a user of the system. The display D may, for example, be a touchscreen, allowing a user to provide input commands to the controller K to perform the processes described herein and / or to modify certain parameters of the controller or the process performed by the controller.Any other suitable form of output or input device, such as indicator lights, switches, push buttons and displays, may be suitably connected to the K controller.

[0062] The controller K may be in communication with one or more components of the system, such as the current measuring means II, 12, the voltage measuring means V and the electrical power supply means G. This communication may be via electrical communication circuits or wireless communication channels of any suitable type, the dotted lines connecting the components of [Fig. 2] schematically representing such communication links. In this way, the controller K may communicate with the current measuring means II and 12 to initiate a current measurement cycle and to receive a first signal and a second signal indicating an electrical current flowing respectively in a first portion of the electrical circuit of the standard loop and in a second portion of the electrical circuit of the standard loop, for example.The controller K can communicate, by transmitting a control signal, with the electrical power supply means G to initiate a current and / or voltage generation cycle and / or to receive in return the generated current and / or voltage. The controller K can communicate with the voltage measuring means V to initiate a voltage measurement process and to receive a detected voltage, for example.

[0063] The disclosure extends to a system 1, which may comprise all or some of the components described herein and illustrated in [Fig.2]. One or more components of the system 1 may be included in a device 200. The device 200 may comprise at least the means for supplying electrical power G and for measuring voltage and current. It may also comprise the controller K and the display D. The controller may further be provided with a set of instructions which, when executed, enable it to perform any step of the measurement and calculation method described herein. In particular, the controller may be programmed to calculate a detected resistance of the entire standard loop and / or of the first electrical circuit portion B1 and the second electrical circuit portion B2 of the standard loop 10.

[0064] In some examples, the standard loop is a metal loop having a relatively high electrical conductivity. Preferably, the electrical resistance value of the standard loop is at most 10 milliOhms, and preferably at most 1 milliOhms. Advantageously, the standard loop may comprise or be entirely made of copper. In order to more effectively detect the resistance of the standard loop, a current of one or more tens of amperes may be generated during the resistance determination procedure. Current values ​​of the order of 50 amperes may be beneficial. The induced current is preferably less than the maximum current that can be supported by the standard loop.

[0065] It is also possible to provide a kit for calibrating a measuring device which may comprise one or more of the components of the system described in the present document, and which may comprise the standard loop 10. It is thus possible to have a complete kit for measuring the resistance of the standard loop 10, in order to allow the entry of its resistance into the measuring device 5 to carry out an effective calibration of this device.

[0066] In view of the above description of the measuring apparatus and its operation, a method for determining the resistance of a standard loop 10 will now be described with reference to the process diagram of [Fig.3].

[0067] A first step SI of the method may be a preliminary step, potentially performed by a user or by an automated handling system, aimed at connecting the standard loop 10 into the electrical circuit via the electrical connection means 101 and 102. This step of the method may be performed by the same entity or the same system or by an entity or a system different from the one that will then execute the steps necessary to carry out the determination of the resistance of the standard loop 10. The standard loop may be connected to the electrical circuit at a first connection point on the loop and at a second connection point on the loop. The standard loop may thus be divided into a first electrical circuit portion and a second electrical circuit portion.These portions may be arranged so that a current applied to the loop is divided into two parallel electric currents which flow in parallel through the first and second electrical circuit portions. It may be advantageous to arrange the electrical connection points on the standard loop so that the resistance of the two electrical circuit portions B1 and B2 of the standard loop has approximately the same resistance. The configuration used for the measurement may be a configuration known as a four-wire measurement, also known as a Kelvin measurement.

[0068] Other steps of the method for determining the resistance of the standard loop 10 may be performed by the user of the system, who may follow written instructions, note the inputs and outputs of the various components of the system and perform appropriate calculations to determine the resistance of the standard loop 10. The user may then enter the determined resistance of the standard loop 10 into the measuring apparatus 5 described in relation to [Fig.l] to enable appropriate calibration of this measuring apparatus 5. As is apparent from the present description, certain steps of the method may be performed by the controller K of [Fig.2].

[0069] Turning to the specific steps of the current determination cycle, the steps are illustrated in [Fig.3]. Once a possible SI connection step has taken place as previously described, the electrical power source G is activated to generate an electric current, which will flow through the standard loop 10 in step S2.

[0070] During step S3, while the current flows in the standard loop 10, a current measurement step is carried out, during which the current passing through the first portion of electrical circuit B1 and the second portion of electrical circuit B2 of the standard loop 10 is detected. The voltage drop at the connection points of the standard loop 10 is detected, preferably at the same time as the current is detected.

[0071] In step S4, a calculation step is performed to determine the total resistance of the standard loop 10. This calculation can be performed using one of the methods described above.

[0072] The steps described herein may be described in a set of instructions. The set of instructions may accompany the system, kit, controller, or device described herein. The instructions may describe the necessary measurement and calculation steps that must be performed as described herein. The instructions may also describe the connection steps described herein. The instructions may be incorporated into computer-executable code. The computer-executable code may be stored in memory accessible to a computing device. The memory may be part of the controller described herein. The instructions, when executed, may cause the controller to implement one or more of the steps described herein. The instructions, when executed by the controller, may cause the controller to be configured according to the controller described herein.

Claims

Claims

1. A method for determining the resistance of a standard loop (10), the standard loop being suitable for use in calibrating a loop electrical conductivity measuring apparatus, the standard loop comprising an electrically conductive closed loop, the standard loop being connected to an electrical circuit at a first connection point on the standard loop and at a second connection point on the standard loop, the first and second connection points defining a first electrical circuit portion (B1) on the standard loop and a second electrical circuit portion (B2) on the standard loop, the method comprising the steps of: • measuring an electric current which flows respectively in the first and second electrical circuit portions of the standard loop when an electric current passes in parallel in the first and second electrical circuit portions;• determination of the total resistance of the standard loop as a function of the electric current measured in the first and second portions of the electric circuit of the standard loop.;

2. The method of claim 1 wherein the electric current, in at least one of the first electrical circuit portion and the second electrical circuit portion, is measured by a current loop.

3. A method according to one or more of the preceding claims, wherein determining the total resistance of the standard loop comprises adding a first resistance value indicating the resistance of the first electrical circuit portion and a second resistance value indicating the resistance of the second electrical circuit portion.

4. A method according to one or more of the preceding claims, wherein determining the total resistance of the standard loop comprises adding a first current value indicative of an electrical current measured in the first electrical circuit portion and a second current value indicative of an electrical current measured in the second electrical circuit portion.

5. A method according to one or more of the preceding claims, wherein determining the total resistance of the loop standard comprises the division of the sum of the values ​​of the electric currents measured respectively in the first portion of the electric circuit and the second portion of the electric circuit by the product of the values ​​of the electric currents measured respectively in the first portion of the electric circuit and the second portion of the electric circuit.

6. Controller (K) configured to determine the resistance of a standard loop (10), the standard loop being suitable for use in calibrating a loop electrical conductivity measuring apparatus, the standard loop comprising an electrically conductive closed loop, the controller being configured to: • output a control signal for applying electrical power to a standard loop; • receive a first input signal indicating an electrical current flowing in a first electrical circuit portion of the standard loop (B 1); • receive a second input signal indicating an electrical current flowing in a second electrical circuit portion of the standard loop (B2); • calculate, based on the first and second input signals, the total resistance of the standard loop.

7. A system for determining the electrical resistance of a standard loop, the standard loop comprising an electrically conductive closed loop, the system comprising: • a first electrical connection means (101) for being connected to a first connection point on the standard loop; • a second electrical connection means (102) for being connected to a second connection point on the standard loop, the first connection point on the standard loop and the second connection point on the standard loop defining a first electrical circuit portion of the standard loop and a second electrical circuit portion of the standard loop; • electrical power supply means (G) electrically connected to the first and second electrical connection means; • first current measuring means (111) for measuring an electric current in the first portion of the standard loop; • second current measuring means (112) for measuring an electric current in the second portion of the standard loop.

8. The system of claim 7, further comprising a controller of claim 6.

9. A kit for calibrating a measuring device, the measuring device being configured to induce an electric current in a loop via a clamp (52) and obtain the value of the current flowing in the loop, the kit comprising: • a standard loop (10) comprising an electrically conductive closed loop; • a system for determining the electrical resistance according to claim 7 or claim 8.

10. The calibration kit of claim 9, further comprising a list of instructions which, when implemented, results in the execution of the steps of the method of any one of claims 1 to 5.

11. The calibration kit of claim 10, further comprising a computer controller, wherein the list of instructions is implementable by the computer controller, for configuring the computer controller into a controller according to claim 6.

12. Device for determining the electrical resistance of a standard loop, comprising a system according to one or more of claims 7 to 8.

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