SU1418689A1 - Data input device - Google Patents

Abstract

The invention relates to automation and measurement technology and can be used for switching and converting signals from parametric sensors into a digital equivalent and introducing the latter into measurement information systems and control computing systems. The aim of the invention is to improve the measurement accuracy of signals from parametric sensors against the background of normal interference acting on sensors. The device contains two pulse generators, two counters, a decoder, a multiplexer, a sensor voltage supply source, a switch, a voltage to time converter, two triggers, two delay elements, two AND elements, and an OR element. The device allows to reduce the effect on the measurement result of the action of normal interference, which is achieved by intermediate processing of the results of individual measurements, 1 sludge. (L

Description

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Od

cx

; The invention relates to auto-iJHxe and measurement technology and can be used to switch and convert signals from parametric sensors (strain gauges, thermometers, resistances, etc.) to the digital equivalent and input the latter into measuring information systems and control outputs. | Complexes.

I The aim of the invention is to increase the accuracy of the input information of 4 tons of parametric sensors when instructed to output a device of digital equivalent proportional to the INPUT signal taking into account the sign.

The drawing shows a functional diagram of the device.

I The device contains the first and second generators 1 and 2 pulses, the elejieHT NOT 3, the analog switch 4, 1 | 1 voltage source 5, the first and second delay elements 6 and 7, the OR element 8, the first and second counters 9 and : | 0, decoder 11, multiplexer 12, sensor group 13, voltage-to-time converter 4, first and second triggers 15 and 16, first and second elements AND 17. and 18, EXCLUSIVE OR 19 and frequency divider 0.

: The device works as follows.

Measured signal U from the sensor. is the sum of the desired signal X, proportional to the measured parameter P, and the additive interference E, described by a polynomial of the order of p.

P-

 X +

-

Zl a, t ;, keo

(one)

no sensor from measurement to measurement; , NJ - the result of a separate measurement

with number i. Vfazheniye for determinant of system

    P

(3)

where t- is the time interval between individual measurements. This determinant, when it is decomposed into the elements of the first column, gives minors ha, which are Vandermonde determinants, and when solving a system of equations, X is obtained

h

.N; m, (-1)

1-1

X

5: M; t (-1)

i-i

(four)

After calculating the minors of ha according to the rules of disclosing the Vandermond determinants (2), the expression (4) is converted to

i-

- N; C; -:, (-1)

M; C ::. (-one)

(five)

binomial coefficients (the number of combinations of p-1 through i-1).

where t. - time of measurement with

the number i (i 1, ..., n); and - coefficients of the approximating polynomial.

Dp of determining the useful signal X (which does not vary in time and depends only on the measured value P and the sensor supply current) it is necessary to solve the system of equations

   N ;,

(2) 55

to 0

where is m; - weight coefficient taking into account the change in the current of the feed;

1 for odd i; Oh at even i.

(6)

Then

N; cn

(-one)

1 (7)

since the sum of the odd coefficients of the decomposition of the binomial Newton stepteP-1

nor n equals 2.

Obino for practical applications is quite sufficient quadratic approximation in approximation of additive noise. In this case, the total number

measurements n 4, and the interference is represented by the dependence

E a. + a, t

+ a

7-.

As follows from (7) for this case (p 4)

 N, - 3N, - N4

From the last expression it follows that in order to measure the input signal from the sensor, alternately from measuring to measuring, switching on and off the sensor supply current, when interfering with a second-order polynomial, make 4 measurements, add them with coefficients 1, -3, 3, -1 respectively and divide the result by 4 "

In the proposed device, this is done as follows.

In the initial state, the counter 9 is reset, the counter 10 and the counting triggers 15 and 16 are set to one.

f

On the first clock signal from generator 1, the triggers 15 and 16 and the counter 10 are set to the zero state, and through the multiplexer 12, the first control sensor is connected to the voltage converter 14 via the first control signal from the decoder 11. The sensors at this moment receive the supply voltage from the voltage source 5 through the switch 4, opened by the control signal from the direct output of the trigger 15, the counter 9 is set to the direct counting mode by the control signal to it. the first control input. Through the delay element 6, which serves to eliminate the influence of transient processes in multiplexer 12 on the measurement result, voltage converter 14 is triggered in a time interval from which the output signal is supplied to elements AND 17 and 18 of the EXCLUSIVE OR 19 circuit, which receives signals from the direct output of the trigger 15 and from the output of the second trigger 16, generates at its output a signal to the element 18, allowing the input of the counter 9 through the element OR 8 of the frequency f from the pulse generator 2, divided

.

3 divider 20 pulse frequency.

The counter 9 is filled for the time interval specified by the voltage converter 14 in the time interval by frequency pulses f / 3. This will be the result of the first measurement of N ,, expression (9). Second clock pulse with

10 of the generator 1 transfers the trigger 15 to a single state, in this case the switch 4 is closed, the counter 9 switches to the countdown mode (the second control input), and the element

15 EXCLUSIVE OR 19 form a prohibitory signal at its outgoing and through element NOT 3 now the element And 17 dp of filling the counter with 9 pulses of frequency f is opened (without

20 3) at the next measurement. As a result, a term 3Nj is added to counter 9 with a minus sign, expression (9),

The next (third) clock pulse from the pulse generator 1 translates trigger 15 into zero and

the trigger 16 is in the unit state, the switch 4 is opened, the counter 9 is set to the direct counting mode (the first control input),

30a, the EXCLUSIVE OR 19 element does not change its state, and the third measurement is again performed with an AND 17 element open, i.e. counter 9 is filled with frequency pulses f at the third measurement and 35 is added to it

40

45

50

55

with a member 3Nj with a plus sign, the expression (9).

The next (fourth) clock pulse from the pulse generator 1 sets the triggers 15 and 16 to one state, therefore, closes the switch 4, changes the output signal of the EXCLUSIVE OR element 19, sets the counter 9 to the countdown mode (second control input). During the filling of the counter 9 with pulses, the element 18 and the filling frequency f / 3, i.e. working frequency divider 20.

On counter 9, the term N is added with a minus sign, expression (9), and the result of the transformations can be read from the older (t-2) bits of the counter 9 (t is the total number of its digits).

Thereby, the operation of the sum of 9 sums received on the counter is executed .. by 4, t, e. get the result

rhenium in the first channel according to you - 1 agenium (9).

I This result is counted on a rehfHCTpaTop by a synchronization signal that arrives at the control input of the device through a delay element 7 (from the trigger 16 when it enters. (Alternate clock pulse from the generator 1, the counter 10 is switched off). and multiplexer

 2 connects the next sensor 13 to the voltage converter 14 and the time interval yo. The result of the recorder is read at This for the time (determined by the delay element 6, after reading the result TaTa, the counter 9 is reset and the cycle of four measurements is repeated for the Next Sensor connected to the multiplexer 12.

invention formula

I A device for inputting information containing two pulse generators, a voltage source, a group of sensors, Two counters, a decoder, a multiplexer, a voltage converter, a separator, two delay elements, an OR element, a NOT element, and the code of the first generator is connected through the first element delays with the control input of the voltage converter, the output of the element OR is connected to the counting input of the first counter, the outputs of which are the information outputs of the device, the output of the second element of the support is the synchronizing output the course of the device, the outputs of the second counter are connected to the inputs of the decoder, the outputs of which are connected to

96

address inputs of a multiplexer, the output of which is connected to the information input of the voltage converter, output of the voltage source is co- connected with the information input of the switch, the output of which is connected to the power inputs of the sensors, the outputs of which are connected to information

the multiplexer inputs, the input of the second delay element is connected to the counting input of the second counter, characterized in that, in order to improve the accuracy of the information entered, two triggers are inserted into the device, a frequency divider, two elements AND, an element. The first trigger is synchronized with the output of the first generator, the direct output of the first trigger is connected to the control input of the switch, the first input of the EXCLUSIVE OR element and the first control input of the first counter, the inverse output of the first trigger is connected to the syn rovho- house second flip-flop and a second control input of the first counter, the second trigger output connected to a counting input of the second counter, and

the second input element is EXCLUSIVE1E OR, the output of which is connected to the third input of the second element AND and through the element NOT to the third input of the first element AND, the output of the second generator is connected to the second input of the first element AND and through the frequency divider to the second input of the second element AND, the output of the converter voltage connected to the first inputs

the first and second elements of AND, whose outputs are connected to the first and second inputs of the element-OR,

Claims (1)

Claim A device for inputting information, containing two pulse generators, a voltage source, a group of sensors, two counters, a decoder, a multiplexer, a voltage converter. A switch, two delay elements, an OR element, a NOT element, the output of the first generator is connected through the first delay element to the control input of the converter voltage, the output of the OR element is connected to the counting input of the first counter, the outputs of which are the information outputs of the device, the output of the second element ^ of the delay is the synchronizing output ohms of the device, the outputs of the second counter are connected to the inputs of the decoder, the outputs of which are connected to the address inputs of the multiplexer, the output of which is connected to the information input of the voltage converter5, the output of the voltage source is connected to the information input of the switch, the output of which is connected to the power inputs of the sensors, the outputs which are connected to the information 10 inputs of the multiplexer, the input of the second delay element is connected to the counting input of the second counter, characterized in that, in order to improve the accuracy of the input In this information, two triggers, a frequency divider, two AND elements, an EXCLUSIVE OR element, a sync input of the first trigger are connected to the output of the first generator, the direct output of the first trigger is connected to the control input of the switch, the first input of the EXCLUSIVE OR element and the first control input of the first counter, the inverse output of the first trigger is connected to the sync input of the second trigger and the second control input of the first counter, the output of the second trigger is connected to the counting input of the second counter and 30 to the second the course of the item is EXCLUSIVE. OR, the output of which is connected to the third input of the second element AND and through the element NOT to the third input of the first element And, the output of the second generator is connected to the second input of the first element And and through the frequency divider to the second input of the second element And, the output of the voltage converter is connected to the first inputs 40 of the first and second AND elements, the outputs of which are connected to the first and second inputs of the OR element.