SU1538238A1 - Device for eliminating chatter of switch contacts - Google Patents

Abstract

The invention can be used in devices of automation, telemechanics and computing. The purpose of the invention is the extension of functionality - achieved by introducing an odd-numbered control unit 4, a delay element 5, a single-shot 6 with a restart, and an element ZI 7. This allowed not only eliminating the contact bounce from one of the outputs when M is turned on the corresponding switch 3, but also in the case of its constant switching on by means of successive M-1 switching on and off any of the remaining switches 3. The device contains N same elements 2I NOR 1 and controlled by the circuit 2. 2-yl.

Description

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3 delays, a one-shot 6 with a rotary start, and element 3 and 7. This, in addition to eliminating contact bounce, forms a sequence of M signals at one of the outputs not only when the corresponding switch 3 is turned on M,

but in the case of its constant switching on by means of sequential M-1 switching on and off any of the remaining switches 3, the device also contains n elements 2 AND-1 1 and a controlled circuit 2, 2 sludge.

The invention is intended for use in devices of automatic and telemechanics and computer technology.

The purpose of the invention is to expand the field of application of the device by generating repeated signals at the k-th output while latching the On state of the on / off switch by turning off and turning off any of the Remaining (k-1) switches.

Fig. 1 shows a functional diagram of the device for eliminating the chatter of contacts and switches; “And FIG. 2 shows timing diagrams for the operation of the circuit.

The device for eliminating the bounce of contacts of switches содержит contains элементов elements 2 AND-NOT 1, the outputs of which are connected to the inputs of the controlled circuit 2, the first inputs are combined, and the second inputs are connected to the second outputs of switches 3 and the inputs of the control unit 4 Oddness, output which is connected to the input of the element 5 delay, the direct input of the one-shot 6 with the turn-I

Torn and the first input element And 7, the output of which is connected to the first inputs of the elements 2 AND-NOT, the second input to the output of the delay element 5, and the third input to the inverse output of the one-shot 6 with a restart. The first terminals of the switches 8 are connected to a common bus. The timing of the single-shot 6 are diode 8, capacitor 9 and resistor 10.

The device works as follows.

In the initial state, the contacts of the switches 3 are closed, at the outputs of elements 4, 5 and 7, the signals of a logical zero act, and at the outputs of elements 6 and 1 and the inputs of the controlled circuit 2 - signals of a logical unit.

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When the contacts of one of the switches open, the first input of the corresponding element 2 AND-NOT 1 and the corresponding input of element 4 receives a bounce signal of the contact of this switch, causing a signal repeating the bounce signal at the output of element 4, the input of delay element 5 and the first input element 7. On the positive edge of the signal coming from the output of element 4 to the direct input of the one-shot with a restart, the pulse of a logical zero is generated at the inverse output of the latter, the duration of which must exceed amb process of contact bounce, and prohibits the passage of signals through debounce elements 7 and 1.

Element 5 is designed to delay bounce signals from the output of element 4.

The delay element 5 prohibits the passage of the first contact bounce signal through the element 7 for a time longer than the turn-on delay time of the one-shot one-shot.

The second and subsequent bounce signals coming to the direct input of a one-shot with a restart, at its inverse output, confirm the level of logical zero by blocking the passage of signals through elements 7 and 1 during the whole process.

At the end of the contact bounce process, the levels of the logic unit are set at the outputs of elements 4-7.

A positive signal arriving at the second inputs of elements 1 provides for setting a logical zero at the output of element 1, to the first input of which a switching signal is received as a logical unit.

51538238

When the contact is triggered back

switch 3, the first zero bounce pulse, arriving at the first input of element 1, causes the appearance of the level of a logical unit at its output and, acting on the corresponding input of element 4, causes the appearance at its output and the first input of the element 7 of the logical zero level, which blocks the element 7 and 1. On the positive edge of the chattering signal that arrives at the direct input of a single-vibrator with a restart, a logical zero pulse is formed at its inverse output, which blocks the passage of chattering pulses through the element s 7 and 1. i

At the end of the contact bounce process, the levels of logic zero are set at the outputs of elements 4, 5 and 7, and the logical unit at the outputs of elements 6 and 1.

With simultaneous or with a certain time shift opening of the contacts of two switches, the operation of the circuit during the action of the chatter signals is similar to the operation with the action of the chatter signals from one contact

At the end of the process of uncoupling and chattering of the contacts at the output of element 4, the first input of element 7 and its output, a logic zero level is established, which blocks the passage of signals from a logical unit through elements 1. Logic unit levels are maintained at all outputs of elements 1.

When one of the contacts of the switches 3 is closed, the first bounce signal entering the corresponding input of element 4 causes the appearance of a logical unit signal at its output, which, acting on the direct input of the one-shot with restart, causes the formation of a logical zero pulse at its inverse output which blocks elements 7 and 1 for the duration of the contact bounce signals.

At the end of the closure process, one of the contacts at one of the inputs of element 4 maintains the level of the logical unit, and at its output, the first input of element 7, the input of the delay element, and the direct input of one vibrator with a restart, the levels of the logical unit are set.

At the end of the impulse

logical zero from the output of the mono-oscillator with a restart at its output and all inputs and output of the element 7 are set to the levels of the logical unit. A positive signal arriving at the second inputs of the elements 1 ensures that a logical zero is set at the output of that element 1 at the first input of which the switch-on signal is stored.

In case it is necessary to form at the inputs of a controlled circuit

signals, the polarity of which must coincide with the polarity of the signals at the contacts of the switches, the elements 2 AND-NOT should be replaced by the elements 2 I.

0 The proposed device for debouncing the contacts of switches and switches provides the possibility of issuing successive M signals at one output not only by turning on

5 M of the corresponding switch 3, but also in the case of its constant switching on by means of sequential (M-1) switching on and off any of the remaining switches.

Claims (1)

0 The invention A device for debouncing contacts of n switches, containing a controlled circuit, n switches, the first outputs of which are connected to the common bus of the device, n elements 2 AND –NE, the first inputs of which are combined, and the outputs are connected to the corresponding inputs of controlled circuits, element I, as well as a single vibrator, characterized in that, in order to expand the field of application of the device, a delay element and an odd parity knot are introduced into it, one vibrator being designed as a single vibrator with repeated charging skom, control inputs node odd connected to second terminals of switches and the second inputs of respective elements 0 2 AND-NOT, the output of the control unit for odd parity is connected to the input of the delay element, the direct input of the one-shot re-starting one and the first input of the AND element, the second input of which is connected to the output of the delay element, and the output to the first inputs of the 2 AND- elements NOT, the third input element AND is connected to the inverse output of the one-shot with a restart. five PG - LTLTL- ----- LJ Fie.2