FR2618269A1 - Remote control line interface - Google Patents

Abstract

An interface is mounted on a remote control line in order to interface push buttons 1 and a logic unit belonging to a centralised switching device. It includes essentially a pulse generator, a resettable monostable 7 and a current limiter 6 having a specified threshold value on the basis of which it controls the monostable 7. The pulses generated by the pulse generator serve to detect a line short-circuit corresponding to the depressing of a push button 1. By virtue of this interface, indicators 2 can be connected in parallel with the push buttons 1, on the remote control line itself, which indicators are representative of one of the states of the logic unit.

Description

 The present invention relates to a remote control power line interface.

 In an electrical installation comprising a pulse circuit connected to various electrical receivers (lighting systems, alarms, motors for actuating doors, shutters, etc.) and a control circuit comprising a certain number of actuators (switches, pushbuttons, etc.), several actuators capable of controlling the same receiver and an actuator capable of controlling more than one receiver, said circuits being connected by a centralized switching device comprising a logic unit capable of ensuring several functions (timer, televisionlon, etc. ), It is of the greatest interest, even essential, to be able to visualize at the level of each actuator, or at the level at the level of some of them, a state of the loglque unit associated with the situation of the receiver controlled by the corresponding actuator. For example, in a building with such an electrical installation, where the lighting of a room can be controlled remotely from one or more places, it is absolutely necessary to be able to view in said place (s) ( s) the instantaneous situation of the lighting in said room.

 Up to now, the most commonly used solution to satisfy this need consists in associating with the control circuit a signaling circuit independent of the latter, said signaling circuit comprising indicators, notably lights, powered with very low voltage current and mounted. adjacent to the actuators of the control circuit to which they correspond. It goes without saying that this solution is neither economical in material nor in workmanship. It also has the disadvantage of being not very flexible in use. In particular, it makes it difficult to modify the allocation of actuators.

 The present invention aims to overcome these various drawbacks. Its purpose is in fact a remote control power line interface by which the conductors of a control circuit are used to supply witnesses representing the logic state of a logic unit. More specifically, this interface is intended for an electrical installation comprising a power circuit rellé, by a centralized switching device comprising a logic unit, to a very low voltage control circuit consisting of two-wire control lines each connected to at least one actuator (push button, in particular) alnsl that a very low voltage signaling circuit comprising indicators (advantageously luminous) associated with at least some of the actuators and representative of a logic state of the loglque unit of the switching device. According to the invention, each command line for which the actuator (s) is (are) associated with a control unit comprises an interface for interface with said actuator (s) and the log unit of the control device. commutatlon, each indicator being connected in parallel to an actuator on said two-wire control line, which is used to act on said temoln.

Other characteristics and advantages of the present invention will become apparent on reading the description which follows, given in relation to the appended drawings in which
FIG. 1 represents a block diagram of the interface according to the invention; and,
Figure 2 represents an electronic diagram of an embodiment of the interface according to the invention.

As can be seen in the figures, a command line interface has
- a two-wire power input (conductors a, O;
- a two-wire line output (conductors f1, g) connected to one or more actuators 1 arranged in parallel, the terminals of each actuator 1 being connected to an indicator 2, advantageously illuminated.

The actuators 1 include solt mechanical contacts (relals, switches, etc.), solt static contacts (semiconductors).

In the sulte, with reference to the figures, one will speak of "push button" to designate the mode of actuation of a mechanical contact, in particular of a relay. It is understood, however, that any actuator belonging to the aforementioned types could be used. Connected directly to each other, this two-wire input and output would form a loop of a traditional control circuit;
- a pulse input of logic Ia d connected to a cycilch pulse generator (not shown) ;;
- a logic line state output e, representative of the state of the push buttons 1 (push button pressed or released establishing or not a short circuit on the line output fl, g; in the figures, a pressed push button corresponds at a value of 1 logical);
- a signaling logic state input f, representative of the state that the witness (s) must take (2).

This interface consists of:
- an OR gate 3, the inputs of which are constituted respectively by the logic state input f and the zen loglque state output;
- a logic pulse generator;
- a NAND gate 4 whose inputs are constituted respectively by the output of the pulse generator d and the output g of the OR gate and whose output h controls a contact 5 disposed on the power input (this contact is closed when output h is at logic I);
- a resettable monostable 7 whose output constitutes the logic state output of line e; and
- a current limiter 6 connected on the one hand between the contact 5 and the push buttons 1 and on the other hand to the resettable monostable 7 this limiter is such that it controls, by the output j, the monostable when it is crossed by a current having reached a predetermined threshold value the choice of which will be explained more quickly, and
- a resettable monostable 7 whose output constitutes the line loglque state output e.

 For the operation of the interface according to the invention, it is advisable to consider two cases according to whether the pushbuttons 1 are released or whether one of them is pressed.

1'- Case where push buttons 1 are released
The logic output e of the resettable monostable 7 is then at #.

A) S1 the logic input f is at, the output g of the OR gate 3 is at and the output of the NAND gate is at 1. The contact 5 is then closed, the line a is energized and the indicators are lit . In this arrangement, the emission of a pulse on the input d of the NAND gate does not change anything at the output h of said gate. The current delivered in the indicators 2 is falble. The threshold value of the current limiter 6 is greater than this current,
B) S1 the logic input is at 1, the output g of the OR gate 3 is 1 and the output of the NAND gate 4 is at, except on the emission of a pulse on t. In this arrangement, the contact 5 closes at each lmpulslon, for the duration of the latter, and the witnesses 2 are traversed by a current, too brief however for them to light up perceptibly to the eye. When the log input f is 1, the 2 indicators are therefore lit.

2n- Case where one of the push buttons 2 is pressed
A) S1 the logic input f is at, that is to say when the lights 2 are on, pressing a push button 1 causes a short circuit on the command line which results, on the one hand the extinction of the temolns 2, which are shunted, and on the other hand a sudden increase in the line current. When this current attelnt the threshold value of the current limiter 6, it controls the resettable monostable 7 whose output e goes to 1 for a period slightly longer than the period of pulses emitted by the pulse generator (fifteen milliseconds, for example, for pulses emitted every ten milliseconds). In this way, pressing a pusher 1 causes the logic output e to go from e to 1, which has the effect of opening contact 5. Contact 5 is made active by the pulses emitted in d, which allow the sampling of the state of the pussies. We are brought back to case 1 B described above.

 B) If the logic input f is at 1, that is to say when the indicators 2 are off, the pressing of a push button 1 causes each pulse emitted by the pulse generator, the passage in the command line of an instantaneous current sufficiently strong to reach the threshold value of the current limiter 6, which controls the resettable monostable, the output of which changes to 1 as has been seen previously.

 The operation of the interface according to the invention is very reliable provided that the threshold value of the current limiter 6 is at the time substantially greater than the currents generated in the control line by electromagnetic disturbances of any origin and, as it was mentioned above, also significantly greater than the current flowing in the control line when the indicators 2 are on.

 The essential advantage of this interface is that it allows viewing at the level of any actuator (push button, etc.) of a control circuit one of the logic states of a centralized log unit, and this by means of indicators connected to the control circuit itself. Thanks to it, moreover, it is possible to provide an actuator with a witness at any time without having to modify the wiring of the installation previously established. Finally, the use of sampling pulses makes it possible to limit the line short-circuit to a very falble average value while ensuring high immunity to brult.

 The present invention is not limited to the example which has just been described; it is, on the contrary, susceptible to modifications and variations that will appear to those skilled in the art.

Claims (2)

 , a current limiter connected to the contact (5), to the actuator (s) (i) and to the resettable monostable (7), said current limiter having a predetermined threshold value and controlling said monostable only when said value threshold is reached, that is to say when an actuator (i) is pressed and. establishes a short circuit on the control line, said threshold value being greater than the usual electromagnetic disturbances.  .a resettable monostable (7) whose output constitutes the line logic state output ;;  a NAND gate (4) whose inputs are constituted respectively by the output of the pulse generator (O and the output (9) of the OR gate (3) and whose output controls a contact (5) disposed on the line control supplied with very low voltage;  .a pulse generator to detect a short circuit when the control line is not continuously energized (actuator closed) ;;  an OR gate (3) whose inputs are constituted respectively by a signal loglque state input (f) representative of the state of the signal (s) (2) and by a loglque state output of line (e) representative of the state of one (s) actuator (s) (1) (open or closed)  1. Interface for an electrical installation comprising a power circuit connected, by a centralized switching device comprising a logic unit, to a very low voltage control circuit consisting of two-wire control lines each connected to at least one actuator (1) alnsl a very low voltage signaling circuit comprising indicators (2) associated with actuator molns (i) and representative of a log state of the logic unit of the switching device, each control line including (the ) actuators is associated with an indicator (2) comprising an interface for an interface said actuator (s) and the logic unit of the switching device, each indicator (2) being connected in parallel to an actuator (1) on said two-wire control line, which is used to act on said indicator, said interface being characterized in that it comprises  2. Interface according to soumlcatlon 1, where the indicators (2) are luminous, characterized in that the threshold value of the current limiter (6) is greater than the current delivered in said indicators when these are on.