SU1403019A1 - Method of monitoring the state of contacts of contact group - Google Patents

Abstract

The invention relates to automation and computer technology and can be applied in devices using information on the transition of contacts of a contact group from one state to another. The aim of the invention is to increase the reliability of determining the state of contacts of a contact group by eliminating the effect of mechanical bounce of contacts of a contact group. The essence of the method consists in fixing an input logic signal characterizing the state of the contact group, starting a time delay block when the input logic level changes, caused by a change in the contact state, forming an output logic signal indicating the state of the contact group at the end of the time delay , transfer of the time delay block to the initial state at each change of the logic signal characterizing the state of the contacts, and the subsequent launch of the block time delay The invention allows to determine the contact state of the contact group independently of the magnitude of the chattering time. 1 il. (L

Description

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The invention relates to automation and computing technology and can be applied in devices that use information about the transition of contacts of a contact group from one connection (for example, closed) to another (open), in particular in. devices of automatic counting the number of manufactured products.

The aim of the invention is to increase the reliability of determining the state of the contact group by eliminating the influence of the mechanical bounce of the contact group's ta contacts.

The drawing shows a diagram of a device that implements a method for determining the contact status of a contact group for the case of contact closure. j The device contains a generator of 1 Reference impulses, a contact block I with a normally open contact and a limiting resistor 4, Lok 5 of the time delay, executed in the form of a pulse counter, containing the counting input 6, input 7 for Start, input 8 of resetting notion and output 9, elements NOT 10 I.P, element AND-NOT 12 and triggers 13-15.

The essence of the method of determining the contact group's contact state is to fix the input logic signal characterizing the state of the contact group, start the time delay block when the input logic signal level caused by the change of the contact state changes, generate an output logic signal indicating the contact group state , after the end of the time delay, the transfer of the time delay block to its original state with each change of the signal characterizing the state - tact, and the subsequent launch of the time delay block.

When the state of the contact group changes, the transition from one state (for example, open) to another (closed) is accompanied by mechanical bounce caused by the elastic properties of the plates on which the contacts of the contact group are fixed.

The mechanical bounce of the contacts causes the appearance of a sequence of changing by the level of spurious signals characterizing the state of the contact group. Single launch

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a time delay block at the first change of the logical signal could cause a false formation of the output signal; however, resetting the time delay block with its subsequent start at each change of the input logic signal prevents the formation of false information about the state of the contact group, i.e. increases the accuracy of the information.

When determining the state of a contact, the contact group's time delay is chosen as a large time interval between any two consecutive inputs and logical signals arising due to contact bounce when the contact state of the contact changes.

A device that implements a method for determining the state of contacts of a contact group when they are closed, works as follows.

When contact 3 of contact block 2 is closed, accompanied by a mechanical bounce, a series of pulses is generated at the output of contact block 2, simultaneously affecting start input 7 and input 8 of resetting the time delay block 5, to which counting input 6 continuously receives reference pulses from generator 1.

Upon arrival at input 7 of the input signal with a zero level, corresponding to the closed state of contact 3, and at its input 6 of the reference pulse, one is recorded in the counter of the time delay unit 5. Since a series of pulses are received during bounce, the next signal with a unit level (coming through the limiting resistor 4 when contact 3 is opened) zeroed the counter of unit 5 time: x intervals at the expense of the HE element 11, i.e. switches block 5 to the initial state. This sequence of recording a single rubbing operation is performed until the contact bounce is completed. At the end of the bounce of the contact group, a zero level is set at the output of the contact block 2 and, therefore, at the start 7 of the block 5 of the time delay, which ensures (through the element HE 10 and the element t И И НЕ 12) the passage of reference pulses to the triggers 13- 15 counter block 5 time delay. After the counter of block 5 is filled (i.e., the end of the time delay), an output signal is generated at its output, indicating the closed state of pin 3.

To form a signal on the state of the contacts of the contact group when they are opened, a similar time delay unit 5 can be used; however, in this case, the signal of the contact unit 2 must be inverted.

The invention makes it possible to reliably determine the state of the contacts of the contact group regardless of the magnitude of the time of contact bounce.

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Claims (1)

Claim Method A method for determining the state of contacts of a contact group, based on fixing an input logic signal, characterizing one of the states of a contact group, forming a time delay interval upon first changing the level of the input logic signal, and generating an output logic signal indicating the state of the contact group at the end of the time delay interval, characterized in that, in order to increase the reliability by eliminating the influence of mechanical chatter, When the state of the contact group changes, the formation of the time delay interval at each change in the input logic signal is stopped and resumed.