SU1728857A2 - Multichannel measuring device - Google Patents

Abstract

The invention relates to a measurement technique and can be applied in information and measurement systems, automatic control systems for measuring the amplitude value and phase shift of periodic signals. The aim of the invention is to improve reliability and increase measurement accuracy. The multi-channel input metering device contains several analog switches 1, each of which contains two p-input multiplexers 2, analog switch 3, analog-digital converter 4, buffer register 5, voltage converter 6, which contains two analog multipliers 7, two integrators 8, control block 9, several counters 10 with inputs of a predvari (L

Description

soldering unit, shaper 11 reference voltage, generator of 12 pulses, divider 13 frequency. New in the device is the introduction of data register 14, a digital-to-analog converter 15, a demultiplexer 16, a reference voltage multiplexer 17, and a synchronization node 18 of the demultiplexer 16 and a multiplexer 17 are entered into control unit 9.

The device allows performance monitoring and improved measurement accuracy. Improving the accuracy of measurement is associated with the possibility of correcting the measured values, the need for which is due to the low temperature and temporal stability of the parameters of multipliers and integrators. 3 il.

The invention relates to a measuring technique, can be applied in information-measuring systems, automatic control systems for measuring the amplitude value and phase shift of periodic signals, and is an improvement of the known device according to the main autom. No. 1617430.

The known multi-channel measuring device contains an analog switch, to the output of which an ADC is connected, a control unit whose outputs are connected to the control inputs of an analog switch, a shaping unit whose inputs are three-phase voltage inputs, a pulse generator with an output connected to a frequency divider, M analog input switches, each of which contains two p-input multiplexers, (p-1) the inputs of the first and p-inputs of the second multiplexer are the inputs of the measured signal Alov and p is the input of the first multiplexer connected to the output of the second, the output of the first multiplexer is the output of the analog switch of input signals, M converters, each of which contains two analog multipliers, the first inputs of which are connected to each other and the output of the corresponding analog switch of input signals and the multiplier outputs are connected respectively to the inputs of two integrators whose outputs are with the converter outputs and connected to the corresponding inputs of the analog switch The oracle, data register, whose information inputs are connected to the ADC outputs, and the data register control outputs and input are data outputs and device control input, respectively, the control unit outputs are connected to integrator zeroing inputs, ADC trigger input, analog input switches, input signals, respectively , M counters, whose synchronization inputs are connected to the left

the control unit inputs connected to the resolution inputs of the analog input switches, the preset inputs and the resolution of the installation of the meters are inputs to the input selection of the device, and the outputs of the meters are connected to the control inputs of the corresponding analog input switches, the outputs of the shaping module 10 are connected to six inputs of the control unit, as well as with the second inputs of the multipliers, the first output of the frequency divider is connected to the synchronization input of the ADC, and the second output is Dinen with the seventh

15 by the input of the control unit, the eighth input of which is connected to the output of the A / D converter, which is the output of the interrupt demand device.

The disadvantages of this device are 20, the limited reliability of operation, which is associated with the inability to conduct monitoring of the device; limited measurement accuracy due to the use of multipliers and integrators, the parameters of which change over time and temperature.

The purpose of the invention is to increase the reliability of operation due to the implementation of performance monitoring, as well as to improve the measurement accuracy due to the correction of measured values.

This goal is achieved by the fact that

35 A device containing an analog switch, to the output of which an analog-to-digital converter (ADC) is connected, a control unit whose outputs are connected to the control inputs of an analog switch 40, a shaping unit whose inputs are three-phase voltage inputs, a pulse generator, to the output of which connected to the frequency divider, M analog input switches, each of

45 of which contains two p-input multiplexers, (p-1) inputs of the first and (p-1) inputs of the second multiplexer are inputs of the measured signals, and the p-input of the first multiplexer is connected to the output of the second, the output of the first multiplexer is the output of the analog switch input signals, M converters, each of which contains two analog multipliers, the first inputs of which are connected to each other and the output of the corresponding analog switch input signals, and the outputs of the multipliers are connected respectively the inputs of two integrators, the outputs of which are the outputs of the converter and are connected to the corresponding inputs of the analog switch, the first data register, whose information inputs are connected to the outputs of the ADC, and the outputs and the control input of the first data register are the data outputs and the first control input of the device, respectively, the outputs the control unit is connected to the integrator zeroing inputs, the ADC trigger input, the resolution inputs of the analog switches of the input signals, respectively, M counters, the inputs from The synchronization of which is connected to the outputs of the control unit connected to the enable inputs of analog switches of input signals, the inputs of preset installation and the enable input of installation of counters are inputs for selecting the input signal of the device, and the outputs of counters are connected to the control inputs of the corresponding analog switches of input signals, the outputs of the forming unit are connected with six inputs of the control unit, as well as with the second inputs of the multipliers, the first output of the frequency divider is connected to the sync input It is used to enable the ADC, and the second output is connected to the seventh input of the control unit, the eighth input of which is connected to the output of the ADC, which is the output of the interrupt demand device, entered the second data register, the information inputs and the control input of which are respectively the data inputs and the second control input of the device A digital-to-analog converter (DAC) whose inputs are connected to the outputs of the second data register, a demultiplexer whose input is connected to the output of the DAC, and the outputs of the demultiplexer are connected to the p-inputs the second multiplexers of the corresponding analog switches of the input signals, the reference voltage multiplexer, the output of which is connected to the corresponding DAC input, the information inputs are connected respectively to each second output of the forming unit, the control unit of the demultiplexer and the reference voltage multiplexer, the inputs of which are connected to the corresponding outputs M of meters, and exits - with

the control inputs of the demultiplexer and the reference voltage multiplexer.

The use of a data register, a digital-to-analog converter, a demultiplexer, and a reference voltage multiplexer makes it possible to increase the reliability of the device and the measurement accuracy. This is due to the fact that the feedback allows you to monitor the operability of the device and carry out the conversion results

5 reference voltages correction of measured values.

Figure 1 is a structural diagram of a multi-channel measuring device; FIG. 2 is a block diagram of the synchronization node; on fig.Z - timing charts ..

The multichannel input measuring device (Fig. 1) with the OST consists of several analog switches 1 of input signals, each of which contains two p-in multiplexers 2,, (p-1) the inputs of the first and (p-1) inputs of the second multiplexer are the device inputs, the p-input of the first multiplexer is connected to the output of the second, the output of the first multiplexer

0 is the output of the analog switch. input signals, analog switch 3, to the output of which an analog-to-digital converter (ADC) 4 is connected, whose outputs are connected to the inputs of the buffer

5, register 5, the outputs and the control input of which are the data outputs and the first control input of the device, respectively. Between the output of each analog switch 1 and the corresponding pair

The 0 inputs of the analog switch 3 include a voltage converter 6, which contains two analog multipliers 7, the first inputs of which are combined and the input of the converter, and the outputs of the multipliers are connected to the inputs of two integrators 8, respectively, whose outputs are the outputs of the converter. The outputs of the control unit 9 are connected to the zeroing inputs of the integrators 8, the control inputs 0 of the analog switch 3, the start input of the ADC 4, the enable inputs of the analog switches 1, respectively. The outputs of the control unit connected to the analog inputs

5 switches 1 are also connected to the synchronization inputs of several counters 10, the preset inputs and the installation enable input of which are the input inputs of the device, and the counter outputs are connected to the control inputs of the analog switches 1, respectively. The inputs of the driver 11 of the reference voltages are the inputs of three-phase voltages, and the outputs are connected to the six inputs of the control unit 9, as well as to the second inputs of the multipliers 7. A frequency divider 13 is connected to the output of the pulse generator 12, the first output of which is connected to the clock input of the ADC 4 and the second output is connected to the seventh input of the control unit 9, the eighth input of which is connected to the output of the A / D converter 4, which is the output of the interrupt demand device. The remaining inputs of the control unit 9 are connected to the corresponding outputs of several counters 10.

The information inputs and the control input of the data register 14 are respectively the data inputs and the second control input of the device, and the outputs are connected to the inputs of a digital-to-analog converter (DAC) 15, the output of which is connected to the input of the demultiplexer 16, the control inputs of which are connected to the corresponding outputs of block 9 control, and the outputs are connected to the p-inputs of the second multiplexers 2 analog switches 1, respectively. The information inputs of the reference voltage multiplexer 17 are connected to each second output of the driver 11, the output is connected to the corresponding input of the DAC 15, and the control inputs are connected to the corresponding control inputs of the demultiplexer 16.

The specific implementation of elements 1-8, 10-13 of the structural scheme of the proposed device is similar to that described in the known. The control unit 9 is made according to the scheme with the inclusion of the synchronization unit 18 (FIG. 2). The synchronization node 18 is constructed using the known laws of combinational logic and contains the elements AND NOT 19-22. The inputs of the synchronization unit 18 are connected to the inputs of the control unit 9, to which the outputs of the counters 10 are connected, and the outputs are connected to the outputs of the control unit 9, to which the control inputs of the demultiplexer 16 and multiplexer 17 are connected.

Consider the generation of control signals by synchronization node 18. When used as a multiplexer 17 and a demultiplexer 16 type 590KH6 chips, the control signals can be represented as follows:

Allow Qi1 x Q.21 x ... x Qy1 x SI2 x Q.22 x ... Qy2xQi3xQ23x ... Qy3, where Qi ... Qy- outputs of the counter 10;

y - the number of outputs of the counter 10, 2log2p;

p - the number of inputs of the multiplexer 2. The signals of the address inputs:

A1 .-. Qif x CH x ... x (V:

 A2 Qi2xQ zx; .. x.Q / L.

A4 Qi1xQ2 x ... xQy. In this case, the cosine reference voltage of the second phase is fed to the input D3, the third

0 phases - to the input D5, the first phase - to the input D6 of the multiplexer 17, and the outputs D3, D5, D6 of the demultiplexer 16 are connected respectively to the p-inputs of the second multiplexers 2 corresponding analogue

5 switches 1.

The device works as follows.

The measured signals Ui ... L) 2p-2, .... UiM ... U2p-2M are fed to the inputs of the device,

0 The operation of the device for processing signals and entering digitized values into a digital computer is described in detail in a known device. The control unit 9 generates zeroing signals Aux. 1 ... Update M, Up. one...

5 Rev. M integrators 8 ,, resolution signals Dis. 1. „Allow. M, control signals Ex. MX of analog switch 3, signal Starting ADC 4, as well as control signals of demultiplexer 16 and multiplexer 17. Shaper 11 generates sine and cosine signals of three-phase voltages A, B, C. Frequency divider 13 generates a synchronization signal of control unit 9 and synchronization signal SI ADC 4.

Consider the operation of the device to improve the reliability of operation and accuracy of measurement. An exemplary amplitude digital code is read into register 14.

0 data when there is a low level signal at the second control input of the device Output. This code is multiplied by the reference voltage of the DAC 15, and the signal from its output goes to the demultiplexer 16. The multi-5 plexer 17 forms the reference voltage of the D / A converter from the cosine voltages of the three phases under the influence of the control signals generated by the control unit 9. From the outputs of the demultiplexer 16 cosine

0, the voltage of the reference amplitude is fed to the p-inputs of the second multiplexers 2 of the corresponding analog switches 1, are converted in the converter 6 into two mutually orthogonal signals, which

5 are passed alternately through the analog switch 3, are converted into ADC 4 into a digital code and are output to the device when the control input of the register 5 has a Low Level input signal. The signal of the end of conversion (CP) is the output signal of the interrupt demand device Tr. A. Using digital values of orthogonal signals, it is possible to determine the amplitude value and phase shift relative to the reference voltage by performing the following operations in a digital computer:

u vuuul p agad-U1

This process can be repeated several times to determine the average values of the amplitude value and phase shift by a known method of measuring the average value of the periodic signals, or by other methods. The mean values of the amplitude and phase shift are compared with the model values. Based on the comparison results, it is concluded that the device is working and the state of the p-inputs of the second multiplexer 2, and also the correction coefficient is determined:

to ,, - Ucp to - tfkp Ku-rj,

where Ucp, pcp are average values of the amplitude. and phase shift;

Uo, p o are exemplary amplitude and phase shift values. As a result of applying correction coefficients when measuring input signal parameters, the measurement accuracy is improved. The evaluation of the state of the remaining inputs of the device can be carried out by

re-passing the input signals by feedback through the p-inputs of the second multiplexers 2. As a result, the measurement results of the first and second passes are compared. According to the results, it is possible to conclude that each input and the device as a whole are operational.

Fig. 3a shows the time diagram of the resolution signal, and Fig. 3b, c, d shows the time diagrams of signals arriving at the address inputs A1, A2, A4 of the demultiplexer 16 and multiplexer 17. Interval

0

five

0

0

0

,,

-P

the time during which the reference voltage is applied to the DAC is equal to the period T of the three-phase network.

The application of the proposed technical solution allows, in comparison with the known, to increase the reliability of operation due to the implementation of the possibility of monitoring the operability of the device, to improve the measurement accuracy. Improving the accuracy of measurement is associated with the possibility of correcting the measured values, the need for which is due to the low temperature and temporal stability of the parameters of the multipliers and integrators of the converter. Thus, only the multiplication error is 1–5%, and the use of correction factors reduces the error of the entire converter to a DAC error, which is 0.1%.

Claims (1)

Claims of the invention Multi-channel measuring device according to the author. St. No. 1617430, from the fact that, in order to improve the reliability and accuracy of measuring the device, a data register, a digital-to-analog converter, a demultiplexer, a reference voltage multiplexer are entered into it, and the control unit additionally contains a synchronization node The information inputs and the data register control input are respectively the data inputs and the second control input of the device, the data register outputs are connected to a group of inputs of a digital-to-analog converter, the input of which is connected to the output terminal. a reference voltage multiplexer, the information inputs of which are connected to the corresponding outputs of the reference voltage generator, the output of a digital-to-analog converter is connected to the information input of the demultiplexer, the address inputs of which are connected to the address inputs of the reference voltage multiplexer and connected to the outputs of the synchronization node whose inputs are connected to the corresponding outputs of the counters, the outputs of the demultiplexer are connected to the corresponding information inputs of the second multiplexers. FIG. J