FR2697927A1 - Computer peripheral unit for controlling electric circuits - uses electromagnetic or electronic relays having operating and test contacts and controlled by computer programme outputs - Google Patents

Abstract

The peripheral unit supplies a weak current whose return or not signifies whether the contacts are open or closed. Each of the input circuits is an 'exclusive or' logic circuit which indicates a change of contact state and a particular contact is identified by the value of an array of resistors activated by operation of the logic circuits. The coil of the relay selected for change is energised via a bistable circuit. ADVANTAGE - Peripheral unit provides simple contact control at low cost.

Description

The present invention relates to a peripheral computer device for enabling the input and output of information corresponding to electrical contacts available to the user. These contacts are actuated (output) and / or tested (input) directly by the user program. This device constitutes a peripheral unit with contacts.

The information processed by a computer program generally finds its origin in a keyboard or a magnetic medium and its final destination is a screen or a printed paper.

There are also complex systems for data acquisition, process control or mechanism controls (digital controls, measuring machines, etc.), but they require significant implementation which leads to high costs.

The device according to the invention allows an application program to activate and test all or nothing electrical contacts intended to control simple mechanisms.

In principle, this device uses a "printer output" for contact action and a "mouse type input" from the computer for contact testing.

At the level of the program executed by the computer, this principle allows the use of existing commands in operating systems, compilers and control software.

At the level of the connection to the computer, this principle allows the use of cards and commercial software.

At the level of the realization of the device, this principle allows the use of attachment cards already developed and contained in the printers and the mice.

Principle of contact action 1) The user program "prints" a series of characters on a "printer" whose address is that of the attachment "output" from the device.

2) This "output" attachment receives the characters and processes the signal as for normal printing.

 3) A decoding cell connected to the attachment selects the contact and determines the action (closing or opening) according to a conventional code: - character A = contact n0 1 - character B = contact n0 2 - character C = contact # 3 and so on.

- upper case character: closing - lower case character: opening 4) The coil of the selected relay is then supplied or not for closing or for opening through a bistable circuit and a suitable amplifier.

5) The open or closed state of the contact is maintained until the next command by the bistable. In the construction of the device, a safety circuit breaker opens all the contacts and interrupts the supply of the circuits.

It should be noted that several contacts can be activated with a single print command.

The conventional code may be different if the number of contacts to be actuated is large.

Principle for testing external contacts 1) A weak current, supplied by the device, is sent to the external contact to be tested or to the contact of a relay actuated by an external circuit. This current returns or not depending on whether the contact is closed or open on an input circuit.

2) Each input circuit is an "EXCLUSIVE" logic circuit which validates its output when the state of the external contact is different from the state of a bistable memorizing the previous situation. The whole being duplicated as many times as there are contacts to be tested.

3) The exit from "EXCLUSIVE OR" becoming 1 means that there is a change of state of the contact. The presence of return current means that there is a transition from the open state to the closed state. The absence of return current means that there is a transition from the closed state to the open state.

4) Resistors X and Y are earthed by a micro-relay activated by the output of "EXCLUSIVE OR". The set of resistors X and
Y corresponding to each contact being in series, the resulting value of X and Y replaces the abscissa and ordinate potentiometers of the mouse.

The value of X and Y is determined by the value of the potentiometers divided by the number of contacts to be tested. The resulting value of the X and Y remaining in series after the grounding of such or such position will allow the program to identify the contact by the coordinates "column" and "line".

5) The output of "EXCLUSIVE OR" is also connected through a non-return diode and according to the new state of the contact on one of the two push buttons of the mouse. The activated circuit will trigger the interrupt (click) which allows reading by the computer.

6) A delay circuit switches the bistable to put it on par with the new state of the contact. The duration of this delay determines the duration of information processing by the computer.

7) The control software provides the application program with the same information as a mouse would have generated.

It should be noted that if several contacts change state at the same time (or the same contact connected to several test circuits), only one will be taken into account, the value of the others being lost.

This drawback is eliminated by adding to the assembly a shift register with parallel outputs which makes it possible to activate the test circuits one after the other.

In the embodiment, there are in a standard box the supply circuits, the printer and mouse cards. On the front side a circuit breaker of the emergency stop type "punch", on the rear side the relay contacts for the outputs and the input terminals for the external contact tests. The device-specific circuits are commercial integrated circuits mounted directly on the printer and mouse cards.

A domestic version can be made by adding female sockets on the rear side with earth distribution. The output contacts supply the corresponding sockets with the mains through a differential protection. The external contact tests can be connected as necessary to current transformers to test the presence or absence of current in an external circuit.

 More complex versions can be made on the basis of screen attachment. In this case, the outputs are made by the display circuits and the inputs by the keyboard circuits with a coding identical to the outputs. This option only works with computers that support multiple displays.

A version for larger computers can be made with an RS 232 type link or a channel attachment.

In each of these versions, a model comprising the outputs alone and a model comprising the inputs only can be produced as a function of the cost price. desired possibilities, space, etc.

A variant of the device may consist of one or more cards without a box and without a supply circuit intended to be installed in another device.

Claims (2)

1) Device constituting a peripheral computer unit, integrated into it or connected by the input / output channels, for controlling one or more electrical circuits according to the logic of a user program characterized in that it comprises electro-magnetic or electronic relays activated by the program output orders and whose contacts are available to be integrated into the electrical circuits to be controlled and / or in that it includes external contact test circuits whose state can be read by the program as input information 2) Device according to claim 1 and in another version characterized by the addition of electrical outlets connected to the sector or to other sources of energy by the contacts.