JP2020017119A - Resistance generation device - Google Patents

Abstract

To reduce time required to generate a desired target resistance value.SOLUTION: A resistance generation device comprises: a current source 3 connected between measurement terminals 52 and drawing current I set to a current value Is from the measurement terminal 52a to output to the measurement terminal 52b; a voltage detection unit 4 detecting a voltage value V1 between the measurement terminals 52; and a processing unit 9 performing resistance generation processing for feedback controlling the current value Is set to the current source 3 based on the voltage value V1 and a target resistance value Rtg. The processing unit 9 measures a resistance value Rpu of a pull-up resistor 54 and a capacity value Cpd of capacity component 57 before the resistance generation processing, and reduces gain of the feedback control as the resistance value Rpu and the capacity value Cpd increase in the resistance generation processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resistance generator that can generate a resistance having an arbitrary resistance value.

  2. Description of the Related Art As a basic type of a resistance generator of this type, a resistance generator disclosed as a conventional technique in Patent Document 1 is known. This resistance generator generates a standard resistance with a known value when calibrating a digital multimeter that measures the resistance value of a resistor or resistance thermometer, or calibrating various thermometers that use a resistance temperature sensor as a sensor. Used as a device to make

  In this case, as a measuring device such as a digital multimeter, a current source for internally generating a measuring current for resistance measurement is provided, and the measuring current is supplied to a resistance to be measured connected between a pair of measuring terminals. At this time, the voltage value of the voltage drop generated in the resistance to be measured (hereinafter, also simply referred to as “voltage drop”) is measured, and the measured voltage drop is divided by the current value of the measurement current to obtain the resistance to be measured. There is a measuring device having a configuration for obtaining the resistance value of the measuring device.

  The resistance generator for a measuring device having this configuration is configured to generate a voltage by generating a voltage, a current source for drawing a measurement current output from between measurement terminals of the measurement device, an ammeter for measuring a current value of the current drawn by the current source. And a voltage source applied between the measurement terminals. In this resistance generation device, the measurement current output from the current source on the measurement device side is drawn by the current source on the resistance generation device side, and the ammeter measures the current value I of the measurement current drawn by the current source. The measured current value I becomes the default value when the current source on the measuring device side is a constant current source (the current value I of the measurement current is a default value). The voltage source generates a voltage with a voltage value V (= I × R) calculated based on the measured current value I (predetermined value) and the resistance value R of the resistor set in the resistance generator. , Applied between the measurement terminals. Thus, the resistance generator can generate a resistance having the set resistance value R between the measurement terminals.

  As another measuring device, a measuring device (thermistor temperature measuring device) 51 shown in FIG. 4 is known. In this measuring device 51, a resistor (thermistor) 53 connected between the measuring terminals 52 a and 52 b is connected to a DC constant voltage Vdd (for example, with reference to the potential of the ground G) from a DC power supply 55 via a pull-up resistor 54. DC + 5V), and a series circuit of a pull-up resistor 54 (resistance value Rpu) and a resistor 53 buffers a voltage (divided voltage) V obtained by dividing the DC constant voltage Vdd (an amplifier having a high input impedance). ) 56, and a data table indicating the relationship between the detected voltage value V1 of the voltage V and the voltage value V1 of the resistor 53 and the temperature (in the circuit configuration shown in FIG. Is gradually changed, and the relationship between each temperature and the voltage value V1 measured at each temperature is shown in a data table obtained by experiment or simulation. Zui and measures the temperature of the resistor 53 (e.g., the temperature of the site where the resistor 53 is disposed).

  On the other hand, as shown in FIG. 5, the resistance generator 41 for the measurement device having this configuration includes a pair of connection terminals 42 a and 42 b connected to the pair of measurement terminals 52 a and 52 b of the measurement device 51 and a pair of connection terminals 42 a and 42 b of the measurement device 51. A current source 43 that sinks the current I from one measurement terminal 52a via the connection terminal 42a and outputs (returns) the current I to the other measurement terminal 52b via the connection terminal 42b, and a voltage V between the connection terminals 42a and 42b. And a voltage measuring unit 44 for measuring the current value I1 of the current I to be drawn into the current source 43 at predetermined time intervals (for example, executing a setting to increase the current value I1 by setting the initial value to zero). Meanwhile, a resistance value R (= V1 / I1) is calculated based on the current value I1 and the voltage value V1 (= Vdd-Rpu × I) of the current voltage V measured by the voltage measuring unit 44, Calculated resistance value And a target resistance value Rtg set in the resistance generation device 41, a feedback control is performed to determine a new current value I1 for the current source 43, and the calculated resistance value R is set to the target resistance value Rtg. And a processing unit 45 that converges to. This allows the resistance generator 41 to generate a resistance having the set target resistance value Rtg between the measurement terminals 52a and 52b.

Japanese Patent Application Laid-Open No. 9-160657 (page 2)

  However, the above-described conventional resistance generator 41 has the following problems to be solved. That is, in the resistance generator 41, the stability and the transient characteristics (rapid response and damping) of the feedback control to be executed are determined by the resistance value Rpu of the pull-up resistor 54 on the measuring device 51 side and the measuring terminals 52a, It is affected by the capacitance value Cpd of the capacitance component 57 that exists equivalently between 52b. For this reason, in the resistance generator 41, in a situation where the resistance value Rpu and the capacitance value Cpd are unknown, the control amount of the feedback control is reduced by sacrificing the transient characteristics in order to surely maintain the above stability. ing. In other words, the gain for calculating the new current value I1 that is the output based on the voltage value V1 that is the input of the feedback control is reduced, and the process until the new current value I1 is set in the current source 43 is reduced. In the meantime, the current source 43 can shift to a state in which the current I is sucked at the current value I1 set immediately before.

  Therefore, the resistance generator 41 has a problem to be solved in that the time required to generate a resistance having the target resistance value Rtg becomes longer because of sacrificing the transient characteristics.

  SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has as its main object to provide a resistance generator capable of shortening the time required to generate a desired resistance value (target resistance value).

  In order to achieve the above object, the resistance generator according to claim 1 applies a DC constant voltage via a pull-up resistor connected to one of the pair of measurement terminals to the other of the pair of measurement terminals. Is applied to a resistor connected between the pair of measurement terminals with reference to the potential of the measurement terminal, and a divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor is detected. Resistance is connected between the pair of measurement terminals of the measurement device having the function of performing the resistance generation process for generating a resistance having a set target resistance value between the pair of measurement terminals. A measuring device connected between the pair of measuring terminals and configured to draw a current having a set current value from the measuring device through the one measuring terminal and perform the measurement through the other measuring terminal. apparatus A current source to be output, a voltage measurement unit that measures a voltage between terminals between the pair of measurement terminals, and the current source based on the voltage between terminals and the target resistance value measured by the voltage measurement unit. A processing unit that performs the resistance generation process of performing feedback control of the current value to be set, wherein the processing unit performs a value measurement process of measuring a resistance value of the pull-up resistor before performing the resistance generation process. By executing, in the resistance generation processing, the gain of the feedback control is reduced as the resistance value measured in the value measurement processing increases.

  In addition, the resistance generator according to claim 2 applies a constant DC voltage to the other measurement terminal of the pair of measurement terminals through a pull-up resistor connected to one of the pair of measurement terminals. It has a function of applying a voltage to a resistor connected between the pair of measurement terminals with reference to the potential, and detecting a divided voltage obtained by dividing a measured constant voltage by the resistor and the pull-up resistor. A resistance generating device that is connected between the pair of measuring terminals of the measuring device in place of the resistor and performs a resistance generating process of generating a resistance having a set target resistance value between the pair of measuring terminals. Is connected between the pair of measurement terminals, and a current having a set current value is sucked from the measurement device via the one measurement terminal and output to the measurement device via the other measurement terminal. Current A voltage measuring unit that measures a voltage between terminals between the pair of measuring terminals, and the current that is set in the current source based on the terminal voltage and the target resistance value measured by the voltage measuring unit. A processing unit that performs the resistance generation processing for feedback-controlling the value, wherein the processing unit measures a capacitance value of a capacitance component existing between the pair of measurement terminals before performing the resistance generation processing. A measurement process is executed, and in the resistance generation process, the gain of the feedback control is reduced as the capacitance value measured in the value measurement process increases.

  The resistance generator according to claim 3 applies a constant DC voltage to the other of the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals. It has a function of applying a voltage to a resistor connected between the pair of measurement terminals with reference to the potential, and detecting a divided voltage obtained by dividing a measured constant voltage by the resistor and the pull-up resistor. A resistance generating device that is connected between the pair of measuring terminals of the measuring device in place of the resistor and performs a resistance generating process of generating a resistance having a set target resistance value between the pair of measuring terminals. Is connected between the pair of measurement terminals, and a current having a set current value is sucked from the measurement device via the one measurement terminal and output to the measurement device via the other measurement terminal. Current A voltage measuring unit that measures a voltage between terminals between the pair of measuring terminals, and the current that is set in the current source based on the terminal voltage and the target resistance value measured by the voltage measuring unit. A processing unit for performing the resistance generation processing for feedback-controlling the value, wherein the processing unit performs, prior to the execution of the resistance generation processing, a resistance value of the pull-up resistor and a capacitance existing between the pair of measurement terminals. A value measurement process for measuring the capacitance value of the component is performed, and in the resistance generation process, the gain of the feedback control is reduced as the resistance value measured in the value measurement process is increased, and the value measurement process is performed. The gain decreases as the measured capacitance value increases.

  In addition, the resistance generator according to claim 4 applies a constant DC voltage to the other measurement terminal of the pair of measurement terminals through a pull-up resistor connected to one measurement terminal of the pair of measurement terminals. It has a function of applying a voltage to a resistor connected between the pair of measurement terminals with reference to the potential, and detecting a divided voltage obtained by dividing a measured constant voltage by the resistor and the pull-up resistor. A resistance generating device that is connected between the pair of measuring terminals of the measuring device in place of the resistor and performs a resistance generating process of generating a resistance having a set target resistance value between the pair of measuring terminals. Is connected between the pair of measurement terminals, and a current having a set current value is sucked from the measurement device via the one measurement terminal and output to the measurement device via the other measurement terminal. Current A current measurement unit that measures a current value of the current sucked from the measurement device via the one measurement terminal; a voltage measurement unit that measures a terminal voltage between the pair of measurement terminals; and the current measurement Calculating the resistance value of the resistor generated between the pair of measurement terminals based on the current value measured by the unit and the inter-terminal voltage measured by the voltage measurement unit, and calculating the calculated value. A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source so that the difference between the resistance value and the target resistance value approaches zero, wherein the processing unit includes the resistance generation unit. Prior to execution of the process, a value measurement process for measuring a resistance value of the pull-up resistor is performed, and in the resistance generation process, the larger the resistance value measured in the value measurement process is, the more the fee is measured. To reduce the gain of the back control.

  Further, the resistance generator according to claim 5 is configured to apply a DC constant voltage to the other of the pair of measurement terminals through a pull-up resistor connected to one of the pair of measurement terminals. It has a function of applying a voltage to a resistor connected between the pair of measurement terminals with reference to the potential, and detecting a divided voltage obtained by dividing a measured constant voltage by the resistor and the pull-up resistor. A resistance generating device that is connected between the pair of measuring terminals of the measuring device in place of the resistor and performs a resistance generating process of generating a resistance having a set target resistance value between the pair of measuring terminals. Is connected between the pair of measurement terminals, and a current having a set current value is sucked from the measurement device via the one measurement terminal and output to the measurement device via the other measurement terminal. Current A current measurement unit that measures a current value of the current sucked from the measurement device via the one measurement terminal; a voltage measurement unit that measures a terminal voltage between the pair of measurement terminals; and the current measurement Calculating the resistance value of the resistor generated between the pair of measurement terminals based on the current value measured by the unit and the inter-terminal voltage measured by the voltage measurement unit, and calculating the calculated value. A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source so that the difference between the resistance value and the target resistance value approaches zero, wherein the processing unit includes the resistance generation unit. Prior to the execution of the process, a value measurement process of measuring a capacitance value of a capacitance component existing between the pair of measurement terminals is performed, and in the resistance generation process, the capacitance value measured in the value measurement process is More listening to reduce the gain of the feedback control.

  In addition, the resistance generator according to claim 6 applies a constant DC voltage to the other measurement terminal of the pair of measurement terminals through a pull-up resistor connected to one measurement terminal of the pair of measurement terminals. It has a function of applying a voltage to a resistor connected between the pair of measurement terminals with reference to the potential, and detecting a divided voltage obtained by dividing a measured constant voltage by the resistor and the pull-up resistor. A resistance generating device that is connected between the pair of measuring terminals of the measuring device in place of the resistor and performs a resistance generating process of generating a resistance having a set target resistance value between the pair of measuring terminals. Is connected between the pair of measurement terminals, and a current having a set current value is sucked from the measurement device via the one measurement terminal and output to the measurement device via the other measurement terminal. Current A current measurement unit that measures a current value of the current sucked from the measurement device via the one measurement terminal; a voltage measurement unit that measures a terminal voltage between the pair of measurement terminals; and the current measurement Calculating the resistance value of the resistor generated between the pair of measurement terminals based on the current value measured by the unit and the inter-terminal voltage measured by the voltage measurement unit, and calculating the calculated value. A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source so that the difference between the resistance value and the target resistance value approaches zero, wherein the processing unit includes the resistance generation unit. Prior to execution of the processing, a value measurement process of measuring a resistance value of the pull-up resistor and a capacitance value of a capacitance component existing between the pair of measurement terminals is performed. To reduce the gain of the feedback control as the resistance value measured at a constant process is large, and to reduce the gain larger the the capacitance value measured by the measuring process.

  The resistance generator according to claim 7 is the resistance generator according to any one of claims 1, 3, 4, and 6, wherein the processing unit determines the voltage value of the DC constant voltage in the value measurement process. While measuring, as the initial value of the current value set in the current source in the feedback control, a current value calculated based on the measured resistance value of the pull-up resistor and the measured voltage value of the DC constant voltage. use.

  The resistance generator according to claim 8 is the resistance generator according to claim 2 or 5, wherein the processing unit determines the voltage value of the DC constant voltage and the resistance value of the pull-up resistor in the value measurement process. While measuring, as the initial value of the current value set in the current source in the feedback control, a current value calculated based on the measured resistance value of the pull-up resistor and the measured voltage value of the DC constant voltage. use.

  In the resistance generation device according to the first and fourth aspects, the processing unit performs the feedback control by decreasing the gain of the feedback control (loop) as the resistance value of the pull-up resistor increases. In this case, the larger the resistance value of the pull-up resistor, the larger the change in the voltage drop caused by the pull-up resistor due to the change in the current value of the current drawn by the current source (that is, the change in the resistance value of the generated resistor). Becomes larger). Therefore, according to this resistance generator, since the gain of the feedback control can be reduced as the resistance value increases, the feedback control can be performed so that the change in the current value does not become too large. The resistance of the target resistance value can be generated in a stable state (a state with little ringing) and at a high speed (in a short time).

  In the resistance generation device according to the second and fifth aspects, the processing unit performs the feedback control by reducing the gain of the feedback control (loop) as the capacitance value of the capacitance component is larger. In this case, the larger the capacitance value of the capacitance component, the greater the delay in the change in the voltage drop caused by the pull-up resistor when the timing of setting the current value from the processing unit to the current source is set as a reference (start) ( In other words, the delay in the change in the resistance value of the generated resistance increases.) Therefore, according to this resistance generating device, the feedback control can be performed while reducing the gain of the feedback control as the capacitance value increases, thereby avoiding the occurrence of ringing due to the delay in the change in the resistance value. The resistance of the set target resistance value can be generated at a high speed in a stable state.

  In the resistance generating device according to the third and sixth aspects, the processing unit performs feedback control by reducing the gain as the resistance value of the pull-up resistor increases, and reduces the gain as the capacitance value of the capacitance component increases. Control. Therefore, according to this resistance generator, as the resistance value is larger, the gain of the feedback loop is made smaller, so that feedback control is performed so that the amount of change in the current value is not too large, or the capacitance value is larger. As the gain of the feedback loop becomes smaller, feedback control can be performed while avoiding the occurrence of ringing due to a delay in the change of the resistance value, so that the resistance of the set target resistance value is further stabilized. And can be generated at high speed.

  In the resistance generation device according to the seventh and eighth aspects, the processing unit is configured to determine the initial value of the current value set in the current source in the feedback control based on the measured resistance value of the pull-up resistor and the measured DC constant voltage. Use the current value calculated by Therefore, according to this resistance measuring device, the resistance of the set target resistance value can be generated in a shorter time as compared with the configuration in which the initial value of the current value set for the current source is set to zero amperes. it can.

FIG. 2 is a configuration diagram of a resistance generator 1 and a measuring device 51. It is a block diagram of an IIR type digital filter. 9 is a flowchart for explaining a value measurement process 20. FIG. 2 is a configuration diagram of a measurement device 51. It is a block diagram of the conventional resistance generator 41 and the measuring device 51.

  Hereinafter, an embodiment of a resistance generator will be described with reference to the accompanying drawings.

  First, the configuration of the resistance generator 1 as a resistance generator will be described with reference to FIG.

  The resistance generating device 1 is a resistance generating device for the measuring device 51 shown in FIG. 4, and as shown in FIG. 1, a pair of connecting terminals 2 a, 52 b connected to a pair of measuring terminals 52 a, 52 b of the measuring device 51. 2b, a current source 3, a voltage detection unit 4, a switch 5, a current detection unit 6, a reference resistor 7, an operation unit 8, a processing unit 9, and an output unit 10, and a pair of resistors having a set target resistance value Rtg. It can be generated between a pair of connection terminals 2a and 2b connected to the measurement terminals 52a and 52b. The measuring device 51 is configured as described in the background art, that is, the DC constant voltage Vdd is applied to the potential of the other measuring terminal 52b (the potential of the ground G via the pull-up resistor 54 connected to one measuring terminal 52a). ) Is applied between the pair of measurement terminals 52a and 52b, and a constant voltage Vdd is measured by a resistor (thermistor or resistance generator 1) connected between the pair of measurement terminals 52a and 52b and the pull-up resistor 54. Is the same as the configuration for detecting the voltage (divided voltage) V obtained by dividing the voltage, the same reference numerals are given and the overlapping description will be omitted.

  Specifically, in the resistance generator 1, the connection terminal 2a is configured to be connectable to the measurement terminal 52a via the connection cable CB1, and the connection terminal 2b is connectable to the measurement terminal 52b via the connection cable CB2. Is configured. The current source 3 is connected between the connection terminals 2a and 2b, and can sink the current I of the current value Is set from the processing unit 9 from the connection terminal 2a side and output the sucked current I to the connection terminal 2b side. Is configured. The voltage detection unit 4 detects a voltage (inter-terminal voltage) V between the connection terminals 2a and 2b, converts the voltage V into a voltage signal Vv whose voltage value changes according to the voltage value V1 of the voltage V, and processes the voltage signal Vv. Output to

  The switch 5 and the reference resistor 7 are connected between the connection terminals 2a and 2b in a state where they are connected in series and in parallel with the current source 3 and the voltage detection unit 4. The switch 5 is configured by a semiconductor switch such as a bipolar transistor or a field-effect transistor, for example, and is controlled by the processing unit 9 to shift to any one of an ON state and an OFF state. Further, the reference resistor 7 is constituted by a fixed resistor having a known resistance value Rr.

  In the present embodiment, the current detection unit 6 is, as an example, one end of the series circuit of the switch 5 and the reference resistor 7 on the connection terminal 2a side (the connection terminal of each of the current source 3 and the voltage detection unit 4 connected in parallel with this series circuit). 2a) and the connection terminal 2a. Although not shown, the current detecting unit 6 is connected to the other end of the series circuit of the switch 5 and the reference resistor 7 on the connection terminal 2b side (in each of the current source 3 and the voltage detecting unit 4 connected in parallel with the series circuit). The connection may be made between the connection terminal 2b) and the connection terminal 2b. With this configuration, the current detection unit 6 converts the current I flowing from the measurement terminal 52a of the measurement device 51 to the connection terminal 2a (also the current flowing from the connection terminal 2b to the measurement terminal 52b of the measurement device 51) into the voltage signal Vi ( The signal is converted into a voltage signal whose voltage value changes in proportion to the current value of the inflowing or outflowing current, and output to the processing unit 9.

  The operation unit 8 includes, for example, an operation switch including a numeric keypad disposed on a panel surface (not shown) of the resistance generator 1, a keyboard connected to the resistance generator 1, and the like. The operation unit 8 is configured to be able to output resistance value data indicating the target resistance value Rtg to the processing unit 9 by being operated by a user of the resistance generator 1.

  The processing unit 9 includes an A / D converter, a CPU, and a memory (both not shown), and controls the current source 3 and the switch 5; voltage measurement processing; current measurement processing; and value measurement processing 20. (See FIG. 3), and a resistance generation process is performed. In this case, in the voltage measurement process, the processing unit 9 samples the voltage signal Vv output from the voltage detection unit 4 with an A / D converter (sampling frequency fs), thereby obtaining instantaneous value data of the voltage signal Vv (the above-described data). (Which is also data indicating the instantaneous value of the obtained voltage V) and stores it in the memory. Further, the processing unit 9 measures the current voltage value V1 of the voltage V between the connection terminals 2a and 2b based on the instantaneous value data. That is, the processing unit 9 configures a voltage measurement unit together with the voltage detection unit 4 and measures the current voltage value V1 of the voltage (inter-terminal voltage) V between the connection terminals 2a and 2b (between the measurement terminals 52a and 52b). I do.

  In the current measurement process, the processing unit 9 samples the voltage signal Vi output from the current detection unit 6 with an A / D converter (synchronizes with the A / D converter for the voltage signal Vv). Thus, the voltage signal Vi is converted into instantaneous value data (which is also data indicating the instantaneous value of the current I flowing into the connection terminal 2a described above) and stored in the memory. Further, the processing unit 9 measures the current value I1 of the current I flowing into the connection terminal 2a based on the instantaneous value data. That is, the processing unit 9 configures a current measurement unit together with the current detection unit 6, and measures the current value I1 of the current I flowing from the measurement device 51 to the connection terminal 2a.

  In the resistance generation processing, the processing unit 9 performs feedback control of the current value Is set in the current source 3 based on the voltage value V1 of the voltage V measured by the voltage detection unit 4 and the target resistance value Rtg. .

  The feedback loop of this feedback control includes a first-order lag element (LPF) composed of a pull-up resistor 54 and a capacitance component 57 on the measuring device 51 side, an A / D conversion process in the processing unit 9 and a resistance value R Is included in the dead time element obtained by the calculation process, and all of these elements are elements that disturb the stability of the feedback control. For this reason, in the present example, the processing unit 9 converts the instantaneous value data of the voltage signal Vv into the instantaneous value data of the voltage signal Vv in order to quickly converge the resistance value R of the generated resistance to the target resistance value Rtg while ensuring the stability of the feedback control. On the other hand, a digital filter process (a process of giving a gain to instantaneous value data while suppressing a gain in a high frequency band to suppress oscillation in a feedback loop) is performed, and a voltage signal Vv obtained by the digital filter process is executed. , The current value Is of the current I set in the current source 3 is calculated. That is, the feedback loop of this example includes a digital filter corresponding to the digital filter processing as a compensation element. In this example, an IIR (Infinite Impulse Response) type digital filter is used as the digital filter.

Since the IIR digital filter is represented by the block diagram shown in FIG. 2, its transfer function is represented by the following equation (1). As a result, the gain of the feedback loop in the resistance generator 1 of the present example including the IIR digital filter increases when the parameter k is large, and decreases when the parameter k is small.
H (z) = k / (1− (1−k) z ⁻¹ ) (1)

Further, the cutoff frequency fc of the IIR digital filter changes in accordance with the parameter k, and the gain of the filter in a frequency region sufficiently lower than the Nyquist frequency (a half of the sampling frequency fs). The characteristic can be approximated to a first-order LPF (low-pass filter). The cutoff frequency fc of this filter when this gain characteristic is approximated to a first-order LPF is expressed by the following equation (2).
fc = k × fs / (2π × (1-k)) (2)

  In the resistance generator 1, the processing unit 9 measures the resistance value Rpu of the pull-up resistor 54 on the measuring device 51 side and the capacitance value Cpd of the capacitance component 57 in the value measurement process 20, as described later. A configuration is adopted in which the parameter k calculated in consideration of the measured resistance value Rpu and the capacitance value Cpd is applied to the IIR digital filter to optimize the compensation by the IIR digital filter. For this reason, in the resistance generator 1, a calculation formula of a parameter k (formula (6) described later) that can optimize the compensation by the IIR type digital filter is stored in the processing unit 9 in advance, and the processing unit 9 performs the calculation. The parameter k is obtained based on the equation, and the parameter k is applied to the IIR type digital filter to execute the above feedback control. Hereinafter, the calculation procedure of the equation for obtaining the parameter k will be described.

The relationship between the gain A _IIR of the _IIR digital filter, the ratio of the resistance value Rpu to the target resistance value Rtg, and the gain margin GM is such that the following equation (3) is satisfied at a frequency f where the phase is delayed by 180 °. Is set.
A _IIR × (Rpu / Rtg) × GM = 1 (3)
In this case, since the phase of the IIR digital filter is delayed by 90 °, the frequency f at which the phase is delayed by 180 ° is the dead time element (1) obtained by the first-order delay element (LPF) and the above-described calculation processing in the processing unit 9 the dead time when converted to the following delay element to the dead time element and T _RC, the dead time in the calculation process when T, the phase in the sum of the 2 Tsunomuda time _{(T RC +} T)) is 90 ° This is the delayed frequency f. Therefore, this frequency f is expressed as 1 / {4 × ( _TRC + T)}. Incidentally, a primary delay above _{T RC} in terms of dead time first-order lag in elements, by using the resistance value Rpu and capacitance Cpd, represented by the formula π / 3√3 × Rpu × Cpd.

Further, the gain A _IIR of the _IIR digital filter at the frequency f (= ω / 2π) when the gain characteristic is approximated to the first-order LPF is expressed by the following equation (4).
A _IIR = | 1 / (1 + jωτ) |
= 1 / √ (1 + 4π ² f ² τ ² )
Here, since τ = 1 / (2π × fc), this is substituted, and
A _IIR = 1 / √ (1 + f ² / fc ² ) (4)

Further, when fc is obtained by substituting the gain A _IIR expressed by the equation (4) into the above equation (3), fc is expressed by the following equation (5).
fc = f / {(Rpu × GM / Rtg) ² -1} (5)
This fc indicates a cutoff frequency fc necessary for obtaining the gain margin GM at a predetermined frequency f.

Further, when the parameter k is obtained from the above equation (2),
k = 1 / (fs / (2π × fc) +1)
Substituting the above equation (5) into this equation gives
k = 1 / (fs / (2π × f) × {(Rpu × GM / Rtg) ² −1} +1)
Becomes Further, by substituting the frequency f (= 1 / {4 × ( _TRC + T)}) satisfying the above equation (3) into this equation, the following equation (6) for the parameter k is finally calculated. Is done.
_{k = 1 / (2fs × (} T RC + T) / π × √ {(Rpu × GM / Rtg) 2 -1} +1)
... (6)

  The output unit 10 includes, for example, a display device such as a display device or a light emitting diode. When the resistance value data indicating the target resistance value Rtg is input from the operation unit 8, the processing unit 9 causes the output unit 10 to display the target resistance value Rtg indicated by the resistance value data, and executes the value measurement process 20. When the resistance that is being generated is stabilized at the target resistance value Rtg as a result of displaying on the output unit 10 indicating that the output is in progress or executing the resistance generation processing (when the generated resistance converges to the target resistance value Rtg). ), An output process for displaying the fact on the output unit 10 is executed.

  Next, the operation of the resistance generator 1 will be described with reference to the drawings. In the resistance generator 1, as shown in FIG. 1, the connection terminal 2a is connected to the measurement terminal 52a of the measurement device 51 via the connection cable CB1, and the connection terminal 2b is connected to the measurement device 51 via the connection cable CB2. Are connected to the measurement terminal 52b.

  In the resistance generator 1, in the initial state (immediately after power-on), the processing unit 9 executes control processing for the current source 3 and the switch 5, and sets the initial value of the current value I1 of the current I to be drawn to zero amperes. To operate the current source 3 and shift the switch 5 to the off state. The current source 3 substantially shifts to the open state when the initial value of the current value I1 is set to zero amperes.

  In this state, when an operation is performed on the operation unit 8 (an operation of setting the target resistance value Rtg) and the operation unit 8 outputs resistance value data indicating the target resistance value Rtg, the processing unit 9 outputs the resistance value data. Is acquired and stored, and the value measurement process 20 is started.

  In the value measurement process 20, first, the DC constant voltage Vdd of the measuring device 51 is measured (step 21). In this case, as described above, since the switch 5 is off and the current source 3 is open, the voltage value V1 of the voltage V between the connection terminals 2a and 2b detected by the voltage detection unit 4 is a DC constant voltage. It is the voltage value of Vdd (also referred to as voltage value Vdd for easy understanding). Therefore, the processing unit 9 performs a voltage measurement process to measure the voltage value V1 for the voltage V between the connection terminals 2a and 2b, and uses the measured voltage value V1 as the voltage value Vdd of the DC constant voltage Vdd. Remember. In this state, in the measuring device 51, the capacitance component 57 is charged to the voltage value Vdd via the pull-up resistor 54.

  Next, the processing unit 9 measures the resistance value Rpu of the pull-up resistor 54 of the measuring device 51 and the capacitance value Cpd of the capacitance component 57 (Step 22). In this case, the processing unit 9 executes current measurement processing, starts storing instantaneous value data of the voltage signal Vi output from the current detection unit 6 in the memory, and executes control processing for the switch 5. To change from the off state to the on state. As a result, the discharge of the capacitance component 57 of the measuring device 51 by the reference resistor 7 is started, and the instantaneous value data of the voltage signal Vi from the start of the discharge (the current I as the discharge current from the capacitance component 57) is stored in the memory. ) Is stored.

  In addition, the discharge from the capacitance component 57 is caused by the voltage of the capacitance component 57 (that is, the voltage value V1 of the voltage V between the connection terminals 2a and 2b detected by the voltage detection unit 4 is equal to the voltage value (Vdd × Rr / (Rr + Rpu)). Therefore, when the processing unit 9 executes the voltage measurement process and detects that the voltage value V1 being measured has become constant, the processing unit 9 determines the instantaneous value of the voltage signal Vi. The storage of the data in the memory is terminated, and the control process for the switch 5 is executed to shift from the ON state to the OFF state.

  The processing unit 9 performs the processing in the state where the discharge of the capacitance component 57 is completed based on the instantaneous value data when the voltage value V1 of the instantaneous value data of the voltage signal Vi stored in the memory becomes constant. The current value I1 of the current I (that is, the current value of the current returning from the DC power supply 55 on the measuring device 51 side to the measuring device 51 side via the pull-up resistor 54, the connection terminal 2a, the switch 5, the reference resistor 7, and the connection terminal 2b). Current value). Further, the resistance value Rpu (= (Vdd−V1) / I1) of the pull-up resistor 54 is calculated (measured) based on the measured current value I1, the measured voltage value V1, and the measured voltage value Vdd. Remember. Further, the processing unit 9 calculates a time constant (Cpd × Rr) for the discharge current based on the instantaneous value data in the discharge state among the instantaneous value data for the voltage signal Vi stored in the memory. At the same time, the capacitance value Cpd of the capacitance component 57 is calculated (measured) from the calculated time constant and the known resistance value Rr and stored.

Subsequently, the processing unit 9 determines a parameter k for the IIR digital filter (Step 23). Specifically, the processing unit 9 calculates the above-described T _RC (= π / 3√3 ×) calculated from the calculated resistance value Rpu and the calculated capacitance value Cpd in the above-described equation (6) stored in the memory in advance. Rpu × Cpd), a known dead time T (sampling cycle: 1 / fs) in the calculation process of the processing unit 9, a known sampling frequency fs, a resistance value Rpu, a set target resistance value Rtg, and a predetermined value. By substituting GM (for example, 14 dB), the parameter k is calculated (determined) and stored. Thereby, the value measurement processing 20 is completed.

  Next, the processing unit 9 performs a resistance generation process to generate a resistance having the set target resistance value Rtg between the connection terminals 2a and 2b (that is, between the measurement terminals 52a and 52b of the measurement device 51). .

  Specifically, the processing unit 9 first executes control processing for the switch 5 to shift to the off state, thereby disconnecting the reference resistor 7 from between the connection terminals 2a and 2b.

  Next, the processing unit 9 executes a control process for the current source 3 to change the current value Is of the current I to be drawn from an initial value (for example, zero amperes) to a predetermined time interval (for example, the sampling period of the A / D converter). : 1 / fs) in steps (increase until the resistance value R calculated as described later reaches the target resistance value Rtg). The current source 3 changes the current value I1 of the sucked current I toward the newly set current value Is. In response to the operation of the current source 3, the current value I1 of the current I flowing from the measuring device 51 via the connection terminal 2a and the voltage value V1 of the voltage V generated between the connection terminals 2a and 2b change. .

  After setting the new current value Is in the current source 3, the processing unit 9 A / D-converts the voltage signal Vv input from the voltage detection unit 4 into instantaneous value data immediately before the predetermined time has elapsed. At the same time, the instantaneous value data is processed by a digital filter (filtering process) to calculate compensated instantaneous value data using the parameter k. Further, the processing unit 9 executes a voltage measurement process, and measures the voltage value V1 of the current voltage V based on the compensated instantaneous value data of the voltage signal Vv. Further, the processing unit 9 calculates the next new current value Is to be set for the current source 3 based on the measured voltage value V1 and the target resistance value Rtg. That is, the processing unit 9 performs a feedback control of calculating a new current value Is based on the measured voltage value V1 and setting the calculated current value Is for the current source 3 by a value (pull-up) of a circuit element on the measuring device 51 side. The processing is executed with a gain corresponding to the parameter k determined in consideration of the resistance value Rpu) of the resistor 54.

  In the resistance generation process in which the current value Is set for the current source 3 is changed stepwise from the initial value of zero as in the present example, the current value I1 of the current I actually drawn by the current source 3 is the initial value. Since the voltage gradually increases from zero, the voltage drop caused by the current I in the pull-up resistor 54 on the measuring device 51 side gradually increases from zero volt. Thus, the voltage value V1 measured by the processing unit 9 in the voltage measurement process gradually decreases from the voltage value Vdd. Therefore, the resistance value R of the resistance generated in the resistance generation processing changes so as to gradually decrease from a value larger than the target resistance value Rtg toward the target resistance value Rtg.

  As described above, this new current value Is reflects the parameter k determined in consideration of the values of the circuit elements on the measuring device 51 side (the resistance value Rpu of the pull-up resistor 54 and the capacitance value Cpd of the capacitance component 57). The resistance value R of the resistance generated by the resistance generator 1 converges to the target resistance value Rtg at a high speed with little ringing since the resistance value R is calculated based on the instantaneous value data of the voltage signal Vv thus obtained. It is something that can be done.

  Accordingly, the resistance generator 1 executes the control process for the current source 3 to execute the process of changing the current value Is of the current I to be absorbed stepwise while calculating the current value Is as described above. The resistance of the set target resistance value Rtg is generated at high speed (in a short time) with little ringing. Further, the processing unit 9 is currently generating when the difference between the voltage value V1 newly measured in the current step and the voltage value V1 measured in the immediately preceding step falls within a predetermined error range. It is determined that the resistance value R of the resistor has converged to the target resistance value Rtg. Further, when the resistance value R of the resistor currently being generated converges to the target resistance value Rtg, the processing unit 9 executes an output process, and notifies the output unit 10 that the generated resistance value is equal to the target resistance value Rtg. Rtg). Thus, the user of the resistance generator 1 can start calibration of the measuring device 51.

  As described above, in the resistance generator 1, the processing unit 9 performs the feedback control with the gain corresponding to the parameter k determined in consideration of the value of the circuit element on the measuring device 51 side (the resistance value Rpu of the pull-up resistor 54). I do. Specifically, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the resistance value Rpu increases, because the parameter k decreases as the resistance value Rpu increases.

  In this case, the larger the resistance value Rpu of the pull-up resistor 54 is, the larger the change of the voltage drop caused by the pull-up resistor 54 due to the change of the current value I1 of the current I sucked by the current source 3 is (that is, the generated resistance). The change in the resistance value R becomes larger). Therefore, according to the resistance generation device 1, the feedback control can be executed such that the gain of the feedback loop is reduced as the resistance value Rpu increases, so that the amount of change in the current value I1 does not become too large. The resistance of the set target resistance value Rtg can be generated in a stable state (a state with little ringing) and at a high speed (in a short time).

  Further, in the resistance generator 1, the processing unit 9 performs feedback control with a gain corresponding to the parameter k determined in consideration of the value of the circuit element on the measuring device 51 side (the capacitance value Cpd of the capacitance component 57). More specifically, since the parameter k decreases as the capacitance value Cpd increases, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the capacitance value Cpd increases.

  In this case, as the capacitance value Cpd of the capacitance component 57 is larger, the change in the voltage drop caused by the pull-up resistor 54 when the timing of setting the current value I1 from the processing unit 9 to the current source 3 is set as a reference (initial period). (That is, the delay in the change in the resistance value R of the resistor to be generated increases). Therefore, according to the resistance generator 1, it is possible to reduce the gain of the feedback loop as the capacitance value Cpd increases, and to execute the feedback control while avoiding the occurrence of ringing due to a delay in the change of the resistance value R. Therefore, the resistance of the set target resistance value Rtg can be generated in a stable state and at high speed.

  Further, in the resistance generator 1, the processing unit 9 sets the parameter k determined in consideration of the values of the circuit elements on the measuring device 51 side (the resistance value Rpu of the pull-up resistor 54 and the capacitance value Cpd of the capacitance component 57). Feedback control is performed with the appropriate gain. More specifically, since the parameter k decreases as the resistance value Rpu increases, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the resistance value Rpu increases, and the parameter increases as the capacitance value Cpd increases. Since k is small, the feedback control is performed by decreasing the gain of the feedback loop as the capacitance value Cpd increases. Therefore, according to the resistance generator 1, as the resistance value Rpu increases, the gain of the feedback loop is reduced, so that feedback control is performed so that the change in the current value I1 does not become too large, or the capacitance value Cpd Is larger, the gain of the feedback loop can be reduced, and the feedback control can be executed while avoiding the occurrence of ringing due to the delay in the change of the resistance value R. Therefore, the resistance of the set target resistance value Rtg can be reduced. Can be generated at a higher speed in a more stable state.

  Further, in the above example, in the resistance generation processing, the initial value of the current value Is set for the current source 3 is zero ampere, but the present invention is not limited to this configuration. For example, in the value measurement process 20, the processing unit 9 measures the resistance value Rpu of the pull-up resistor 54 and the voltage value Vdd of the DC constant voltage Vdd. Further, the DC constant voltage Vdd is applied to the resistance generator 1 that generates the resistance having the target resistance value Rtg while being connected in series with the pull-up resistor 54. Therefore, the current value I1 of the current I drawn by the current source 3 when the resistance generator 1 is generating the resistance having the target resistance value Rtg is calculated as Vdd / (Rpu + Rtg). Therefore, in the resistance generation processing, the processing unit 9 sets the resistance value Rpu of the pull-up resistor 54 and the voltage of the DC constant voltage Vdd measured in the value measurement processing 20 as initial values of the current value Is set for the current source 3. A current value (Vdd / (Rpu + Rtg)) calculated based on the value Vdd can also be used.

  According to the resistance generator 1 employing this configuration, the resistance of the set target resistance value Rtg is further reduced as compared with the configuration in which the initial value of the current value Is set for the current source 3 is set to zero amperes. Can be generated on time.

  Further, the above-described resistance generating device 1 employs a configuration in which the processing unit 9 does not calculate the resistance value R of the resistance currently being generated, and generates a resistance having the set target resistance value Rtg. It is not limited to this configuration. For example, the processing unit 9 calculates the resistance value R of the resistance currently being generated in the resistance generation processing, and sends the current value to the current source 3 based on the difference between the calculated resistance value R and the target resistance value Rtg. It is also possible to adopt a configuration in which a new current value Is to be set is calculated to generate a resistance having the set target resistance value Rtg. In the resistance generation device 1 having this configuration, the processing unit 9 measures the current value I1 of the current I drawn by the current source 3 based on the voltage signal Vi output from the current detection unit 6 in the resistance generation processing. Based on the measured current value I1 and voltage value V1, the current resistance value R (= V1 / I1) of the resistor currently generated between the connection terminals 2a and 2b is calculated. Further, the processing unit 9 calculates the next new current value Is to be set for the current source 3 based on the difference between the calculated current resistance value R and the target resistance value Rtg. Note that other operations are the same as those of the resistance generator 1 described above, and thus description thereof is omitted.

  Also in the resistance generator 1 having this configuration, the processing unit 9 performs feedback control with a gain corresponding to the parameter k determined in consideration of the value of the circuit element on the measuring device 51 side (the resistance value Rpu of the pull-up resistor 54). . Specifically, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the resistance value Rpu increases, because the parameter k decreases as the resistance value Rpu increases.

  Therefore, the resistance generator 1 can also perform the feedback control so that the gain of the feedback loop is reduced as the resistance value Rpu increases, so that the amount of change in the current value I1 does not become too large. The resistance of the target resistance value Rtg can be generated in a stable state (a state with little ringing) and at a high speed (in a short time).

  Further, in the resistance generator 1, the processing unit 9 performs feedback control with a gain corresponding to the parameter k determined in consideration of the value of the circuit element on the measuring device 51 side (the capacitance value Cpd of the capacitance component 57). More specifically, since the parameter k decreases as the capacitance value Cpd increases, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the capacitance value Cpd increases.

  Therefore, even with this resistance generating device 1, the feedback control can be performed while reducing the gain of the feedback loop as the capacitance value Cpd increases, thereby avoiding the occurrence of ringing due to a delay in the change of the resistance value R. Therefore, the resistance of the set target resistance value Rtg can be generated in a stable state and at high speed.

  Also in the resistance generator 1, the processing unit 9 determines the parameter k determined in consideration of the values of the circuit elements on the measurement device 51 side (the resistance value Rpu of the pull-up resistor 54 and the capacitance value Cpd of the capacitance component 57). Feedback control with a gain corresponding to. More specifically, since the parameter k decreases as the resistance value Rpu increases, the processing unit 9 performs the feedback control by decreasing the gain of the feedback loop as the resistance value Rpu increases, and the parameter increases as the capacitance value Cpd increases. Since k is small, the feedback control is performed by decreasing the gain of the feedback loop as the capacitance value Cpd increases. Therefore, according to the resistance generator 1, as the resistance value Rpu increases, the gain of the feedback loop is reduced, so that feedback control is performed so that the change in the current value I1 does not become too large, or the capacitance value Cpd Is larger, the gain of the feedback loop can be reduced, and the feedback control can be executed while avoiding the occurrence of ringing due to the delay in the change of the resistance value R. Therefore, the resistance of the set target resistance value Rtg can be reduced. Can be generated at a higher speed in a more stable state.

  Also, in the resistance generating device 1 configured such that the processing unit 9 calculates the resistance value R of the resistance currently being generated in the resistance generation processing, the resistance value of the current value Is set for the current source 3 is also set in the resistance generation processing. The initial value can be set to zero amperes, or based on the set target resistance value Rtg, the resistance value Rpu of the pull-up resistor 54 measured in the value measurement process 20 and the voltage value Vdd of the DC constant voltage Vdd. The calculated current value (Vdd / (Rpu + Rtg)) can also be used.

1 Resistance generator
3 Current source
4 Voltage detector
6 Current detector
9 Processing unit 51 Measuring device 52a, 52b Measuring terminal 54 Pull-up resistor 55 DC power supply
I Measurement current I1 Current value Rtg Target resistance value V1 Terminal voltage Vdd DC constant voltage

Claims (8)

A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source based on the inter-terminal voltage and the target resistance value measured by the voltage measurement unit,
The processing unit performs a value measurement process of measuring a resistance value of the pull-up resistor before performing the resistance generation process,
In the resistance generation processing, a resistance generation device that reduces the gain of the feedback control as the resistance value measured in the value measurement processing increases. A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source based on the inter-terminal voltage and the target resistance value measured by the voltage measurement unit,
Prior to performing the resistance generation process, the processing unit performs a value measurement process of measuring a capacitance value of a capacitance component existing between the pair of measurement terminals,
In the resistance generation processing, a resistance generation device that reduces the gain of the feedback control as the capacitance value measured in the value measurement processing increases. A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
A processing unit that performs the resistance generation process of performing feedback control on the current value set in the current source based on the inter-terminal voltage and the target resistance value measured by the voltage measurement unit,
Prior to execution of the resistance generation process, the processing unit performs a value measurement process of measuring a resistance value of the pull-up resistor and a capacitance value of a capacitance component existing between the pair of measurement terminals,
In the resistance generation processing, a resistance that decreases the gain of the feedback control as the resistance value measured in the value measurement processing increases, and decreases the gain as the capacitance value measured in the value measurement processing increases. Generator. A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A current measurement unit that measures a current value of the current sucked from the measurement device through the one measurement terminal;
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
Calculating a resistance value of a resistor generated between the pair of measurement terminals based on the current value measured by the current measurement unit and the inter-terminal voltage measured by the voltage measurement unit; A processing unit that performs the resistance generation process of performing feedback control of the current value set in the current source so that the difference between the calculated resistance value and the target resistance value approaches zero,
The processing unit performs a value measurement process of measuring a resistance value of the pull-up resistor before performing the resistance generation process,
In the resistance generation processing, a resistance generation device that reduces the gain of the feedback control as the resistance value measured in the value measurement processing increases. A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A current measurement unit that measures a current value of the current sucked from the measurement device through the one measurement terminal;
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
Calculating a resistance value of a resistor generated between the pair of measurement terminals based on the current value measured by the current measurement unit and the inter-terminal voltage measured by the voltage measurement unit; A processing unit that performs the resistance generation process of performing feedback control of the current value set in the current source so that the difference between the calculated resistance value and the target resistance value approaches zero,
Prior to performing the resistance generation process, the processing unit performs a value measurement process of measuring a capacitance value of a capacitance component existing between the pair of measurement terminals,
In the resistance generation processing, a resistance generation device that reduces the gain of the feedback control as the capacitance value measured in the value measurement processing increases. A DC constant voltage is connected between the pair of measurement terminals via a pull-up resistor connected to one of the pair of measurement terminals with reference to the potential of the other measurement terminal of the pair of measurement terminals. The resistance is applied between the pair of measurement terminals of the measurement device having a function of detecting the divided voltage obtained by dividing the measured constant voltage by the resistor and the pull-up resistor while applying the voltage to the resistor. A resistance generator that is connected in place of the body and performs a resistance generation process of generating a resistance having a set target resistance value between the pair of measurement terminals,
A current connected between the pair of measurement terminals, a current having a set current value is drawn from the measurement device via the one measurement terminal, and is output to the measurement device via the other measurement terminal. Source
A current measurement unit that measures a current value of the current sucked from the measurement device through the one measurement terminal;
A voltage measurement unit that measures a terminal voltage between the pair of measurement terminals,
Calculating a resistance value of a resistor generated between the pair of measurement terminals based on the current value measured by the current measurement unit and the inter-terminal voltage measured by the voltage measurement unit; A processing unit that performs the resistance generation process of performing feedback control of the current value set in the current source so that the difference between the calculated resistance value and the target resistance value approaches zero,
Prior to execution of the resistance generation process, the processing unit performs a value measurement process of measuring a resistance value of the pull-up resistor and a capacitance value of a capacitance component existing between the pair of measurement terminals,
In the resistance generation processing, a resistance that decreases the gain of the feedback control as the resistance value measured in the value measurement processing increases, and decreases the gain as the capacitance value measured in the value measurement processing increases. Generator.   The processing unit measures the voltage value of the DC constant voltage in the value measurement process, and as the initial value of the current value set in the current source in the feedback control, the measured resistance value of the pull-up resistor and 7. The resistance generator according to claim 1, wherein a current value calculated based on the measured DC constant voltage is used.   The processing unit measures the voltage value of the DC constant voltage and the resistance value of the pull-up resistor in the value measurement process, and measures the initial value of the current value set in the current source in the feedback control. 6. The resistance generator according to claim 2, wherein a current value calculated based on a resistance value of the pull-up resistor and a measured DC constant voltage value is used.

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