Method and apparatus 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 device. 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 portion of the electrical circuit (B1) on the standard loop and a second portion of the electrical circuit (B2) on the standard loop.The method includes the steps of measuring a current flowing respectively in the first and second portions of the electrical circuit of the standard loop when an electric current is passed in parallel in the first and second portions of the electrical circuit and determining the total resistance of the standard loop as a function of the electric current measured in the first and second portions of the electrical circuit of the standard loop.

Description

Title of the invention: Method and device for determining the electrical resistance of a calibration 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. Previous art

[0002] Devices for measuring the electrical conductivity of a loop in an electrically conductive network, the loop being a metallic loop formed by a succession of metallic elements constituting the electrically conductive network, by means of a clamp coupling to the loop, are known. Calibration methods for this type of device generally involve providing a calibration device, and the calibration of the measuring device is carried out 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 device. Improving the reliability of 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 is suitable for calibrating measuring devices to measure the electrical conductivity of a loop in an electrically conductive network. Furthermore, the invention relates to a calibration kit for a measuring device to improve the calibration procedure. In particular, the invention allows the resistance of a loop to be determined without having to disconnect two ends of the loop, by using a current flowing unidirectionally through the loop. The invention implements a measurement method that uses a current flowing in parallel through two parts of an electrical circuit within the loop.

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

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

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

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

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

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

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

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

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

[0013] The process may further include a preliminary step of: • connection of the reference loop in the electrical circuit to the first connection point on the reference loop and to the second connection point on the reference loop.

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

[0015] The controller can be configured to add a first value indicating the resistance of the first portion of the electrical circuit to a second value indicating the resistance of the second portion of the electrical circuit 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 and second sections 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 calibration 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 characteristics: • a first means of electrical connection to be connected to a first connection point on the reference loop; • a second means of electrical connection to be 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 portion of the electrical circuit of the standard loop and a second portion of the electrical circuit of the standard loop; • means of supplying electrical power electrically connected to the first and second means of electrical connection; • the first means of current measurement to measure an electric current in the first portion of the standard loop; • second means of current measurement to measure an electric current in the second portion of the standard loop.

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

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

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

[0021] According to one aspect, the invention relates to a calibration kit for a measuring device, the measuring device being configured to induce an electric current in a loop by means of a clamp and to 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 this disclosure.

[0022] The calibration loop may be a metallic loop, with an electrical resistance of at most 10 milliohms, and preferably of at most 1 milliohm. The calibration loop may be a copper loop.

[0023] The calibration loop can be a closed loop, optionally provided with a mechanical link and not welded, to connect the two ends of the loop.

[0024] The kit may further include a list of instructions which, when implemented, produces the execution of the steps of the process according to this disclosure.

[0025] The list of instructions can be implemented by a computer controller, to configure a controller as described in this disclosure.

[0026] The kit may further include a controller as described in this 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 attached figures where the same references designate identical or functionally similar elements from one figure to another:

[0029] Fig. 1 is a schematic representation of a measuring device suitable for implementing a method of controlling a clamp coupled to a device.

[0030] Figure 2 is a diagram of an example of means for determining 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 determining the resistance of a standard loop 1, said standard loop 1 being suitable for facilitating the calibration of a loop electrical conductivity measuring device 5. The measuring device 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 metallic loop, of an electrically conductive network, so as to determine the electrical conductivity of said loop. An example of a relevant measuring device is described in French patent no. FR 3 091 760 B, but determining the resistance of a standard loop may be useful for other examples of devices.

[0033] Figure 1 is a schematic representation of such a measuring device 5 suitable for measuring the conductivity of a loop 6, or for checking an electrical circuit. This checking can be implemented in a ship or aircraft, for example, or in any other electrical circuit, to verify its integrity and electrical resistance. To ensure the accuracy of such a device, it is necessary to calibrate it with a reference 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 reference loop to allow the calibration of a measuring device 5.

[0034] The measuring device 5 is connected to a removable clamp 52 which grips one of the metallic elements belonging to the loop 6 being tested for electrical continuity. The clamp 52 is connected to a power supply 51 which delivers an electric current that is transmitted by electromagnetic induction from the clamp 52 to the loop (current Cl) when the clamp 52 surrounds an element of the loop 6. The same clamp 52 collects the electric current C2 flowing 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 its electrical continuity.

[0035] The clamp 52 includes: an electrical circuit 520, such as a coil made up of a winding of conductive wire, configured to inject the current Cl 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 check 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 clamp identifier, at least one or more of the following quantities: a current value from a first test, referred to as the reference current; the phase shift value from the first test, referred to as the reference current, between the calibration current injected into said clamp and the current collected by the clamp during this calibration; the number of turns in the clamp; and the coefficient of the clamp cable. Some of these quantities allow the calculation of an "offset" when a subsequent measurement is performed 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 required in the measurement of the electrical continuity of the conductor or circuit being measured.

[0037] The first test or calibration of the clamp 52 is carried out before its marketing, for example during its manufacture, 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 current value and the reference phase shift value, of the clamp 52 stored in the storage memory 521 of the latter, a processing unit, in the form of a microprocessor 54, configured to calculate, on the basis of the measurements made by the clamp 52, the value of the resistance of the loop 6 representative of its electrical conductivity and optionally to determine any wear on the clamp 52, for example, at each use, after a predetermined number of uses, or whenever 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 taken (current and / or frequency) during tests of said clamps, which may occur at each use, after a predetermined number of uses, or when the user voluntarily wishes to test the clamp being used. The database may include a wear indicator (in the form of a bit that can take a value of "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 allows the resistance of the loop 6, formed by the metal elements joined at points A, B, C and D, to be measured by placing the clamp 52 on the perimeter of one of the metal elements belonging to this loop, namely the metal element 51 in this example.

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

[0042] The method, devices and system that are the subject of this disclosure are intended to allow at least the determination of the resistance of such a standard loop.

[0043] Known methods for measuring the resistance of a standard loop consist of creating a detachment point in the standard loop so that the two ends of the standard loop can be separated from each other, transforming the standard loop into a unidirectional electrical conductor. In a second step, the resistance of the conductor forming the standard loop is measured by passing an electric current unidirectionally from one end to the other, with 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 method of measuring the resistance of a standard loop has 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 calibration loop complete, in other words, without interrupting the conductivity of its electrical circuit. The new process takes into account several laws: • Kirchhoff's current law: The sum of the currents entering a node is equal to the sum of the currents leaving the same node. • Kirchhoff's voltage law: In any mesh of a network, in the quasi-stationary regime approximation and provided that the variations of 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] Figure 2 is a schematic representation of a system comprising means for implementing the new process. These means and the process will be described in parallel with reference to Figure 2.

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

[0047] The system and its components are designed to determine the resistance of a standard loop 10. The standard loop 10 can be an electrically conductive closed loop. The loop can be closed and welded or can have ends connected by a mechanical link. Regardless of its form, the inventor has determined that it is advantageous to be able to determine the resistance of the standard loop without altering its shape or construction. This represents an advantage over prior art methods for measuring the resistance of standard loops, 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 unknown and can influence the actual resistance of the standard loop.

[0048] The system includes 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 link, for example an electrical clamp, a mount in which the ring of the standard loop is received to hold it and to connect it electrically, or any other form of electrical and / or mechanical connection allowing an electrical connection to be established between the ring of the standard loop and the electrical power supply means G. The electrical power supply means G include, in particular, an electrical power supply 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 supply G. These conductors can take any suitable form to carry the electrical current from the electrical power supply 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 makes it possible to measure the voltage drop across the reference loop 10. Consequently, a voltage detector V can be connected so as to allow the voltage across the reference loop 10 to be measured. The connection can be made either via the electrical connectors 101 and 102, or through the electrical conductors 141 and 142, or by connecting directly to the reference loop 10 at or near the location of 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 terminals of the reference 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 implemented 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 sensing 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 first and second connection points respectively on the standard loop such that the standard loop is divided into two distinct electrical circuit portions B1 and B2. When an electric current is applied between the electrical connectors 101 and 102 to flow through 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 the 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 power supply G provides an electric current, preferably a stabilized electric current, to the reference loop 10. The electric current flowing through each portion of the reference loop, B1 and B2, is measured by the current measuring means II and 12, which may be in the form of current loops, electric coils connected to a multimeter to provide a simple output of a value, or a digital or analog signal representing a detected current. They may also be more sophisticated devices that perform 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 reference loop is repeated to obtain a plurality of measured current values. In particular, obtaining a plurality of measured current values ​​involves applying a plurality of different voltages to obtain different measured current values ​​in the reference loop.

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

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

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

[0059]

[0060]

[0061] • U is the voltage drop at 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 calibration loop 10 • It is the total current measured in a first portion of the B1 standard loop electrical circuit • 12 is the total current measured in a second section of the circuit B2 standard loop electrical • 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 calibration loop: / 1 + / 2 R —U* „- / 1 * / 2 It will also be appreciated that another calculation can be carried out by first calculating RI as U / I1; calculating R2 as U / I2 and adding RI to R2 to find the total resistance R of the standard loop 10. The system in [Fig. 2] may further include a controller K, which may comprise 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 designed to receive signals from various components of the system described herein. The controller K may be designed to communicate input values ​​between the processor 151, the memory 152, and the input / output modules 153 in order to perform certain calculations on the inputs and output the results. The controller K may include outputs to communicate output parameters to a display D, which may show the parameters or output values ​​to a system user. The display D may, for example, be a touchscreen, allowing a user to provide input commands to the controller K to execute the processes described herein and / or to modify certain parameters of the controller or the process executed by the controller.Any other suitable form of output or input device, such as indicator lights, switches, pushbuttons and displays, can be appropriately connected to the K controller.

[0062] The controller K can communicate with one or more system components, such as the current measurement means II, 12, the voltage measurement means V, and the electrical power supply means G. This communication can be via electrical communication circuits or wireless communication channels of any suitable type, the dashed lines connecting the components in [Fig. 2] schematically representing such communication links. In this way, the controller K can communicate with the current measurement 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 reference loop and in a second portion of the electrical circuit of the reference 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 the generated current and / or voltage back. The controller K can communicate with the voltage measurement 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 include all or part of the components described in this document and illustrated in [Fig. 2]. One or more components of system 1 may be included in a device 200. The device 200 may include at least the electrical power supply means G and the voltage and current measurement means. It may also include 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 in this document. In particular, the controller may be programmed to calculate a detected resistance of the entire reference loop and / or of the first electrical circuit portion B1 and the second electrical circuit portion B2 of the reference loop 10.

[0064] In some examples, the reference loop is a metallic loop with relatively high electrical conductivity. Preferably, the electrical resistance of the reference loop is at most 10 milliohms, and preferably at most 1 milliohm. Advantageously, the reference loop may comprise or be entirely made of copper. To more effectively detect the resistance of the reference loop, a current of one or more tens of amperes may be generated during the resistance determination procedure. Current values ​​on the order of 50 amperes may be beneficial. The induced current is preferably less than the maximum current that the reference loop can withstand.

[0065] A calibration kit for a measuring device can also be provided, which may include one or more of the components of the system described in this document, and which may include the standard loop 10. A complete kit can thus be provided to measure the resistance of the standard loop 10, in order to allow its resistance to be entered into the measuring device 5 to carry out an effective calibration of this device.

[0066] In view of the above description of the measuring device and its operation, a method for determining the resistance of a standard loop 10 will now be described with reference to the process diagram in [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 to the electrical circuit via the electrical connection means 101 and 102. This step of the method may be performed by the same entity or system, or by a different entity or system, that will subsequently perform the steps necessary to determine 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 can thus be divided into a first portion of the electrical circuit and a second portion of the electrical circuit.These sections can be arranged so that a current applied to the loop is split into two parallel electrical currents flowing in parallel through the first and second sections of the electrical circuit. It can be advantageous to arrange the electrical connection points on the standard loop so that the resistance of the two electrical circuit sections B1 and B2 of the standard loop has approximately the same resistance. The configuration used for the measurement can be a configuration known as a four-wire measurement, also known as a Kelvin measurement.

[0068] Other steps in the process of determining the resistance of the standard loop 10 can be carried out by the system user, who can follow written instructions, note the inputs and outputs of the various system components and perform appropriate calculations to determine the resistance of the standard loop 10. The user can then enter the determined resistance of the standard loop 10 into the measuring device 5 described in relation to [Fig. 1] to allow proper calibration of this measuring device 5. As can be seen from the present description, some steps of the method can be carried out by the controller K of [Fig. 2].

[0069] Moving on 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 described previously, the power supply G is activated to generate an electric current, which will flow through the standard loop 10 at stage 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 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 instruction set may accompany the system, kit, controller, or device described herein. The instructions may describe the necessary measurement and calculation steps to 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

Demands

1. Method for determining the resistance of a standard loop (10), the standard loop being suitable for use in calibrating a loop electrical conductivity measuring device, 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 portion of the electrical circuit (B1) on the standard loop and a second portion of the electrical circuit (B2) on the standard loop, the method comprising the steps of: • measuring an electric current flowing respectively in the first and second portions of the electrical circuit of the standard loop when passing an electric current in parallel in the first and second portions of the electrical circuit;• 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 standard loop's electrical circuit.

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

3. A method according to one or more of the preceding claims, wherein the determination of the total resistance of the calibration loop includes the addition of a first resistance value indicating the resistance of the first portion of the electrical circuit and a second resistance value indicating the resistance of the second portion of the electrical circuit.

4. A method according to one or more of the preceding claims, wherein the determination of the total resistance of the calibration loop comprises the addition of a first current value indicating an electric current measured in the first portion of the electrical circuit and a second current value indicating an electric current measured in the second portion of the electrical circuit.

5. A method according to one or more of the preceding claims, wherein the determination of the total resistance of the loop The standard includes 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.

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 device, the standard loop comprising an electrically conductive closed loop, the controller being configured to: • output 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 (B1); • receive a second input signal indicating an electric current flowing in a second portion of the electrical circuit of the standard loop (B2); • calculate, on the basis of 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; • of the first current measurement means (111) for measuring an electric current in the first portion of the standard loop; • of the second current measurement means (112) for measuring an electric current in the second portion of the standard loop.

8. System according to claim 7, further comprising a controller according to claim 6.

9. Calibration kit for a measuring device, the measuring device being 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 the loop, the kit comprising: • a calibration loop (10) comprising an electrically conductive closed loop; • a system for determining electrical resistance according to claim 7 or claim 8.

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

11. The calibration kit of claim 10, further comprising a computer controller, wherein the instruction list is capable of being implemented by the computer controller, to configure the computer controller into a controller according to claim 6.

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

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