RU86729U1 - PRECISION SIMULATOR OF DISCRETE ACTIONS OF RESISTOR RESISTANCE VALUES - Google Patents

Abstract

A precision simulator of discrete increments of resistor values, containing a reference resistor of one of the selected values in the range of 100 ÷ 800 Ohms with current and potential outputs at each end, characterized in that the current output from one end of the reference resistor is connected to the current output of an additional serial resistive divider , consisting of ten series-connected equal in nominal value of 11 or 22 Ohms, precision resistors, and the potential output from a common point is connected between the reference resistor and the series resistive divider, as well as from the connection points of the divider resistors, and the potential output from its other end are alternately connected to the inputs of the additional multiplexer, whose common output and potential output from the other end of the reference resistor are the output of a precision simulator, and the serial resistive divider is shunted precision resistor, equal in value to the resistor of the series resistive divider and connected with its findings to common to it the connection point of the reference resistor and the series resistive divider, as well as to its second terminal, which has current and potential terminals.

Description

The invention relates to measuring equipment, in particular, to metrological certification of multichannel multifunctional means for measuring electrical quantities (Measuring and computing systems "IVK"). It can be used to set physical high-precision parameters of the resistance, voltage, and current to the input of the IVK, which is designed to service strain gauge and thermistor sensors that change their resistance when the value of the physical parameter varies, as well as other types of sensors with an output voltage or current signal.

Small-sized resistors (from 100 Ohm and above), for example, Р2-67, С2-29С, etc., of sufficiently high accuracy (up to 0.001%) and T.K.S. = ± (5-10) - are known 10 ^-6 1 / ° С. Corresponding sets of such resistors (HP) at normal temperature (20 ± 2 ° С) can be used at the measuring inputs of the IVK as sensor equivalents for checking the metrological characteristics of the IVK.

The main disadvantage of using such series-connected sets of resistors is the low accuracy of low-resistance resistors (up to ten Ohms), manufactured with an accuracy of at least 0.5%, by which a stepwise increment of the resistance of the sensor is simulated. A similar problem arises in the manufacture of parallel analog-to-digital and digital-to-analog converters, where serial low-resistance resistive dividers are used to reduce noise and increase speed.

Basically, when simulating a stepwise change in the resistance value of the sensor equivalent, shunt resistors are used, as indicated above, successive dividers of low-resistance resistors that simulate stepwise increments of the sensor resistance value are rarely used due to their low accuracy (± 0.5%). At the same time, the selection of shunt resistors when choosing 10-40 increments of the sensor equivalent is a rather difficult task due to the selection of their ratings, especially for different values of the equivalent (reference resistor) of the sensors, for example, 100, 120, 200, 400 and 800 Ohms and the development of the process automation.

Known devices made on this principle:

- "A device for automating research on metrological characteristics." Proceedings of TsAGI, M., 1981, issue 2105, p. 75 Beklemishchev A.I. and Sudakov V.A .;

- Copyright certificate of the USSR N 1551979, cl. G01B 7/18, 1987, Shevchuk. V.

These devices relate to means for measuring non-electric quantities by electrical measuring transducers and can be used to simulate a stepwise increment of resistance equivalent to tensoresistive or thermoresistive only single sensors during calibration of measuring systems. Here, an increase in accuracy is achieved by reducing the influence on the output signal of the resistance value of the simulator of the transient resistance of the switching element included in the serial switching circuit of the shunt resistor, which performs an abrupt change in the resistance of the simulator (reference resistor) and reduces the error introduced due to the magnitude and instability of the resistance of the switching item.

All devices described in analogs solve particular problems and are not adapted for automatic verification of multichannel multifunctional measuring and computing complexes (IVK).

This factor is especially important when checking the metrological characteristics of CPI.

The device described in patent RU No. 2023979, IPC G01B 7/18,

"The simulator of the discrete increment of the resistance of the strain gauge" is the closest to the claimed solution and is used as a prototype, which describes the structure and general parameters of the construction and communication with the input and output measuring circuits of the device. The simulator is powered by a stable current, and the signal is removed by potential buses, but a change in the parameter of the reference resistor is achieved by shunting it in each case with a selectable resistor, and the problem of compensating the transition resistance of a contactless key made on a MOS transistor is solved.

The disadvantages of the proposed prototype are the construction of a simulator of abrupt changes in the reference resistor due to a set of difficult to select different values of shunt resistors, when simulating the scale of the working range of sensors of different ratings and the process of automating verification of the IVC, as well as the lack of accuracy in reproducing the increment of resistance due to series connection with a shunt resistance of the switching element and the instability of its transition resistance.

A technical solution is proposed to increase the accuracy and speed of a precision simulator of discrete increments of resistor values for a selected series of sensor resistance values in the range of 100-800 Ohm, when one serial precision resistive divider is used, connected in series with a reference resistor, which leads to the universality of the proposed device for simulating a stepwise increment of resistance, voltage and current when simulating any type of sensors.

The technical result is achieved by the fact that in a precision simulator of discrete increments of resistor values containing a reference resistor with current and potential terminals at each end, the current output from one end of the reference resistor is connected to the current input of an additional series resistive divider, consisting of n equal in series at the nominal value of precision resistors, and the potential output from the common connection point of the reference resistor and the series resistive about the divider, as well as from the points of connection of the resistors of the divider and the potential output from its other end, are alternately connected to the inputs of an additional multiplexer, the common output of which and the potential output from the other end of the reference resistor are the output of a precision simulator, and the serial precision resistive divider is shunted by a precision resistor, equal in value to the resistor of the series resistive divider and connected by its terminals to the common connection point of the reference resistor and Hence the resistive divider, and to its second terminal, and a current having a potential conclusions

Figure 1 shows a diagram of a precision simulator of discrete increments of the resistance values of the resistor.

The simulator consists of a series connection of a reference resistor R _N , one of the selected sensor equivalent ratings

R _N = 100 ÷ 800 Ohm, with a serial divider of n resistors R (1 + 5) shunted resistor R (1 + δ) and an additional multiplexer where:

(1 ÷ 10) - resistor R (1 + 5) (for example, the selected nominal value of 11.22 Ohms) with a manufacturing error of not more than ± 0.05%;

(11) - shunt resistor R (1 + 5) (for example, the selected nominal value of 11.22 Ohms) with a manufacturing error of not more than ± 0.05%;

(12) - reference resistor R _N with a manufacturing error of not more than ± 0.01% (sensor simulator);

(13) multiplexer.

I - stable current of an external weighted power source of a precision simulator of discrete increments of resistor resistance values;

U ₁ - voltage removed from R (1 + 5);

U ₁₀ - voltage removed from 10 × R (1 + 5);

δ is the maximum error of the resistor no more than ± 0.05%.

A precision simulator of discrete increments of resistor values works as follows: when an n-series divider is shunted by a resistor (11) R (1 + δ) (at selected resistor values (11.22) Ohms, the equivalent divider resistance (for a ten-digit divider) will be:

Wherein:

R _e1 ... R _e10 - equivalent resistance of the resistive divider, from which the output voltages are removed (without taking into account the voltage drop across the reference resistor, which ultimately sums up):

For the two types used by ten-digit resistive dividers:

R = 11 Ohms ± 0.05% and R = 22 Ohms ± 0.05%:

R _e1 = 1 Ohm ± 0.05% ÷ R _e10 = 10 Ohm ± 0.05%

R _e1 = 2 Ohms ± 0.05% ÷ R _e10 = 22 Ohms ± 0.05%

In this case, the error in the generated values (R _e1 -R _e10 ) is an order of magnitude smaller than the error in commercially available low-impedance resistors (R≤10 Ohm) with an error of ≥ ± 0.5%, while the industry has now mastered the production of resistors with a nominal value of more than 10 Ohms Grade ± 0.05%.

The inputs of the multiplexer (13) alternately connect the connection points of the resistors (1, 2, 3-10, n), from which the voltages (U ₁ ÷ U ₁₀ , un) applied to the common output of the multiplexer are removed. The voltage U taken from the output of the multiplexer (13) and the potential output of one end of the reference resistor (12) is supplied to the input of an external instrument operational amplifier with a large input resistance, which eliminates the influence of the resistances of the keys of the multiplexer (13). Since a high-precision low-impedance serial divider is used, which is especially important for constructing parallel analog-to-digital and digital-to-analog converters, this ensures a sufficiently high speed by reducing the duration of transients.

To automate the calibration process of measuring systems, an automatic calibrator of measures (AKM) has been developed, which is used to reproduce the increment of resistance, voltage and current for the Tensor measuring and computing complex (see, for example, the article “Providing metrological tests of the TENZOR measuring and computing complex in “Sensors and Systems” magazine, 2006, No. 8. p. 34-36, where the basis of AKM is the proposed technical solution.

Claims (1)

A precision simulator of discrete increments of resistor values, containing a reference resistor of one of the selected values in the range of 100 ÷ 800 Ohms with current and potential outputs at each end, characterized in that the current output from one end of the reference resistor is connected to the current output of an additional series resistive divider , consisting of ten series-connected equal in nominal value of 11 or 22 Ohms, precision resistors, and the potential output from a common point is connected between the reference resistor and the series resistive divider, as well as from the connection points of the resistors of the divider and the potential output from its other end, are alternately connected to the inputs of an additional multiplexer, whose common output and potential output from the other end of the reference resistor are the output of a precision simulator, and the serial resistive divider is shunted precision resistor, equal in value to the resistor of the series resistive divider and connected with its findings to common to it the connection point of the reference resistor and the series resistive divider, as well as to its second terminal, which has current and potential terminals.