SU1132356A1 - Device for detecting pulse loss - Google Patents

Abstract

A device for detecting a loss of pulses, containing two switches, two counters, two pulse drivers, a trigger, an And element, and a pulse generator, the output of which is connected to the first inputs of the switches, the first outputs of which are connected to the counting inputs of the corresponding counters, while the control input of the first switch is connected with the first output of the trigger, the second output of which is connected to the input: the control of the second switch, the second input of which is connected to the second input of the first switch, so that, in order to expand its functionality, an element of code comparison is entered into it, the inputs of which are connected to the corresponding outputs of counters, the installation inputs of which are connected to the second outputs of the respective switches, the second inputs of which are connected to the trigger input and through the first pulse shaper with the first input bus device, with the first and second outputs, trigger connected to the additional control inputs, respectively (L but the second and first switches, the third inputs are from Connected with the first input element And through the second pulse shaper with the output of the comparison code element, the second input of the element And connected to the second input bus of the device, and its output is the output of the device .. 00 SP a

Description

.1 The invention relates to a pulse technique and can be used to control pulse sequences, in particular, to detect the loss of output pulses from a magnetically inductive sensor of a turbine distributor. A device for detecting a loss of pulses is known, containing a square detector, two delay elements, a NOT element, and. the element And, which allows you to detect the loss of an unlimited number of pulses in a pulse sequence lj. A disadvantage of this device is that it is designed to control a pulse sequence with a fixed frequency and cannot be used in cases where the frequency of the monitored pulses varies smoothly within wide limits. The closest in technical essence to the invention is a device for detecting failures in a pulse sequence, comprising a trigger, an ISI element, two switches, two pulse drivers and two counters, with the installation input of the first counter through the first pulse driver connected to the control input of the first switch and to the first output of the trigger, the input of which is the first input of the device, and the second output is connected to the control input of the second switch and via the second pulse shaper - with input The home of the second counter, whose addition and subtraction inputs are connected respectively to the first and second outputs of the second switch, the first and second inputs of which are the second and third inputs of the device, are connected to the corresponding inputs of the first switch, the first and second outputs of which are respectively, to the addition and subtraction inputs of the first counter, the output of which is connected to the first input of the NAND element, the second input of which is connected to the output of the second counter, and the output is the output of the device. The disadvantages of this device are its operation only with fixed frequencies of impulse sequences, as well as the impossibility of detecting the loss of several pulses in a row. The purpose of the invention is to expand the functionality of the device, namely the loss of several pulses of pulses in a pulse CHOii sequence with a smooth change. frequency over a wide range. The goal is achieved in that a device for detecting a pulse loss, containing two switches, two counters, two pulse drivers, a trigger, an element And a pulse generator, the output of which is connected to the first inputs of the switches, the first outputs of which are connected to the counting inputs of the corresponding counters. , while the control input of the first switch is connected to the first trigger output, the second output of which is connected to the control input of the second switch, the second input of which is connected to the second input of the first switch, a code comparison element is introduced, the inputs of which are connected to the corresponding meter outputs, the installation inputs of which are connected to the second outputs of the corresponding switches, the second inputs of which are connected to the trigger input and through the first pulse shaper to the first input bus of the device, the first and second outputs the trigger is connected to the additional control inputs of the second and first switches, respectively, the third inputs of which are connected to the first input of the And element and through the second form spruce pulse output code comparing element, wherein the second input of AND gate is connected to the second bus input device, and its output is the output device. FIG. 1 is a functional diagram of a device for detecting loss of pulses; in fig. 2 - timing diagrams for the operation of the device. The device for detecting the loss of pulses contains two switches 1 and 2, two counters 3 and 4, two pulse formers 5 and 6, trigger 7 element 8, pulse generator 9, the output of which is connected to the first, inputs of switches 1 and 2, first outputs which are connected to the counting inputs of the corresponding counters 3 and 4, while the control input of the first switch 1 is connected to the city, the first output of the trigger 7, the second output of which is connected to the control input of the second switch 2, the second input of which is connected to the second input of the first switch 1, as well as the comparison element 10, the inputs of which are connected to the corresponding outputs of counters 3 and 4, the installation inputs of which are connected to the second outputs of the respective switches 1 and 2, the second inputs of which are connected to the input of trigger 7 and through the first pulse shaper 5 with the first input bus 11 device, while the first and second outputs of the trigger 7 are connected to the additional control inputs of the second and first switches 2 and 1, respectively, the third inputs of which are connected to the first input of the element And 8 and through the second form pulse generator 6 with the output of the comparison element codes 10, the second input of the AND 8 element is connected to the second input bus 12 of the device, and its output is the output of the device 13. The switch 1 contains the elements AND 14-16 and the element OR 20, the switch 2 - the elements And 17-19 and element OR 21. The device works as follows. The controlled pulse sequence is fed to the first input bus 11 of the device (Fig. 2a), jf h with which the input of the pulse former is connected 5. For each input pulse, the pulse shaper 5 generates a pulse at its output, the duration of which is given by the maximum input frequency U T is the maximum increment of the pulse periods following each other; n is the number of successive impulses (maximum but possible). The pulses from the output of the former (Fig. 2 S) are fed to the input of the trigger 7 and the inputs of the element And 15 of the switch 1 and the element 1 And 1 iS of the switch 2, which are the second inputs of these switches. Depending on the state of the trigger 7, the generated pulses go through the elements 15, OR 20 of the switch 1 to the input of the meter installation 3 or through the elements AND 18, OR 21 of the switch 2 to the input of the installation of the counter 4. If the trigger 7 is in the single state, then the pulses from the generator 9 arrive at the first input of the switch 1 and through the element 14 that enters composition (FIG. 2b) to the input of the counter 3, while the code accumulated in the previous period is stored in the pulse counter 4. When the next pulse arrives at the input bus 11 of the device, pulse shaper 5 generates a pulse, which through elements AND 18, OR 21 of switch 2 sets the counter 4 to the zero state, and on the trailing edge triggers the trigger 7 to the zero state. At that, elements 14 and 16 of switch 1 and element 18 of switch 2 are closed, and element 15 of a switch 1 and switch 1 and elements 17 and 19 of switch 2 open and the pulses from the generator 9 begin to flow to the input of counter 4 (Fig. 22) . In view of the fact that trigger 7 is switched on the falling edge (on a negative differential), and the counter that stores the code for the number of pulses accumulated in the previous period, resets on the leading edge (on a positive differential). Ccj-o- shaper 5 (Fig. 2a), equal to „„, .. m The number of codes in counters 3 and 4 can only be achieved if the pulses in the monitored pulse sequence are lost, while the comparison element 10 and the shaper of pulses 6 The pulse from the output of the pulse shaper 6, p oyd through IV element is supplied to the output 13 (FIG. 26), indicating the loss of momentum in the controlled sequence. To detect the sequential disappearance of several pulses, the output of the pulse generator 6 connections to the inputs of elements 16 and 19. In the event of the loss of several pulses, one of the counters 3 or 4 stores the code of the previous perische, and the input of the other continuously receives pulses from the generator 9. When equality of codes is achieved in the counters, the element of comparison of codes 10 and the pulse shaper 6 are triggered, the output pulse

, 51

which is set to zero with a counter, at the input of which the impu is received; After that, whether or not the next pulse arrives at the device input, the process repeats. The pulse shaper 6 produces short pulses, the duration of which is determined by the time when the counters 3 and 4 are set to the zero state. To eliminate the generation of pulses at the output, the device has a control input 12.

323566

The permissive signal to this input is supplied only for the time of monitoring the input pulse sequence. Thus, this device

5 makes it possible to detect the loss of several pulses of a different order in a controlled pulse sequence with a smooth change in frequency. Use of the device in the secondary device

10 turbine meter will significantly improve the measurement accuracy in an emergency.

I I I

GPP

n P I n

f

i

t t

Claims (1)

DEVICE FOR DETECTING PULSE LOSS, containing two switches, two counters, two pulse shapers, a trigger, an element And the pulse generator, the output of which is connected to the first inputs of the switches, the first outputs of which are connected to the counting inputs of the corresponding counters, while the control input of the first switch is connected to the first output of the trigger, the second output of which is connected to the control input of the second switch, the second input of which is connected to the second input of the first switch, which consists in the fact that, in order to expand its functionality, a code comparison element is introduced into it, the inputs of which are connected to the corresponding counter outputs, the installation inputs of which are connected to the second outputs of the corresponding switches, the second inputs of which are connected to the trigger input and through the first pulse shaper to the first input bus of the device, with the first and second outputs. the trigger is connected to additional <8 control inputs of the second and first switches, respectively, the third inputs of which are connected to the first input of the I and Pere second pulse shaper with the output of the code comparison element, the second input of the And element connected to the second input bus of the device, and its the output is the output of the device.