SU1584095A1 - Device for protection from contact chatter - Google Patents

Abstract

The invention can be used to protect the mechanical contacts in the devices forming, issuing and processing information from chattering. The purpose of the invention is to simplify and expand the functionality of the device by reducing hardware costs and generating signals about the input and removal of the input command. The goal is achieved by introducing two elements OR-NOT 1 and 2. The device also contains one-shot 3, 4, input bus 5, output buses 6, 7, 8. 2 Il.

Description

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The invention relates to a pulse technique and can be used in devices for forming, issuing and processing information for protection against the bounce of the contacts of mechanical switches.

The purpose of the invention is to increase reliability with simultaneous expansion of functionality due to JQ generation of command start and end signals.

FIG. 1 shows a functional and diagram of the proposed device; fia FIG. 2 - timing diagrams that show the operation of the device.

The bounce protection device contains OR-NOT elements 1 and 2, one- Vibrators 3 and 4, input bus 5 and output tires 6-8.20

The first input of element 1WEA-NOT 1 is connected to the output of the one-shot 4 and the first additional output bus 7, the second input is connected to the input bus 5, the output of the element OR-NO 1 is connected 25 to the first input of the element OR-NOT 2 and through the one-shot 3 - to the second to the additional output bus 8 and the second input of the element OR NOT 2, the output of which is connected to the input of the one-shot 30 and the output chic 6.

The bounce protection device operates as follows.

In the initial state, the contacts of the switch (not shown) are open. 35 At the same time, on the input bus 5 there is a level t (Fig. 2a), and on output PSNs 7 and 8 - levels O (Fig. 26 and g (Respectively), at the output of the OR-NOT 1 element - O level) (Fig. 2c ), and 4d at the output of the element OR-NOT 2 and exit-Noy bus 6 - level 1 (fig.2d).

At the moment of issuing the command from the switch on the input bus 5, the O level is set. At the same time, the output signal of the element OR NOT HE is 1 signal level

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О on Г, and at the output of the element OR-HE 2 and the output bus 6 - from 1 to O, which corresponds to the leading edge of the pulse formed on the output bus 6. Under the action of a positive voltage drop formed at the output of the OR element -NOT 1, the launch of the 3-vibrator 3, which forms a pulse with a duration longer than the contact bounce time. This pulse arrives at the output bus 8 and the second input element OR NOT

The bounce pulses generated on the input bus 5 at the moment of issuing a command from the switch are inverted by the element OR NOT 1. However, these pulses do not affect the pulse generated on the output bus 6, because at the second input of the element OR NOT 2 at this time a positive impulse from the output of the single-vibrator 3 acts, as a result of which during the action of this impulse, the output of the OR-NOT 2 element and the output bus 6 is held at the level O. After the contact bounce stops, the level O is set at the input bus 5, The OR-NOT 1 element is level 1, and the output of the OR-NOT 2 element and the output bus 6 continues to maintain level O.

At the moment of removing the command from the switch on the input bus 5, the level 1 is set. At the same time, the output voltage of the OR-NOT 1 element produces a voltage drop from 1 to O, and the output of the OR-NOT 2 element and output bus 6 - from O to 1 , which corresponds to the falling edge of the pulse generated on the output bus 6. Under the action of a positive voltage drop generated at the output of the OR-NOT 2 element, a single vibrator 4 is started, which generates a pulse with a duration longer than the contact bounce time. This impulse arrives at the output bus 7 and the first input of the element OR NOT 1. At the same time, during the time of action of this impulse, the outputs of the elements OR OR NOT 1 and 2 hold the levels O and 1, respectively, and the bounce pulses generated at that time at the entrance. bus 5 does not affect the operation of the device, since the output of the element OR NOT 1 is not passed. After the contact bounce, level 1 is established on the input bus 5 and the outputs of the elements OR NO 1 and 2 continue to respectively, the levels are O and 1. Upon completion of the formation of a pulse by the one-shot 4, the device returns to its original state and is ready to work again.

Thus, as a result of the operation cycle of the device, an impulse is formed on the output bus 6 with a duration equal to the time interval between moments.

Tami filing on the switch and remove from it the command to be executed. On the output tires 8 and 7, pulses are formed, the leading fronts of which coincide with the moments of respectively giving and removing the same command.

The device thus generates output signals for several analyzed characteristics of the input command.

Claims (1)

Formula from, brend The device for protection against contact bounce, containing the first and second one-shot and element OR, and the output of the second one-shot is connected to the first input of the element OR, the second input of which is the input device bus, output bus, characterized in that, in order to increase reliability with simultaneous expansion of functional capabilities, the OR element is designed as an OR-NOT element and a second OR-NOT element is introduced, the output of which is connected to the input of the second one-shot and is an output bus, the first additional output bus is connected to the output of the second one-shot, and the output of the first element OR is NOT connected to the first input of the second 5 element OR-NOT and the input of the first single vibrator connected by its output to the second the input of the second element OR- and the second additional output bus. FIG. 2