JPS6041900A - Control inhibiting circuit at multiplex selection - Google Patents

Abstract

PURPOSE:To inhibit control when two or more of plural control item selecting relays operated and lower the price of this control inhibiting circuit by driving ordinary relays by an electronic circuit instead of mercury relays of polarized relay structure in a control inhibiting circuit at multiplex selection. CONSTITUTION:One side of contacts rl1-2-rl1-n of plural control item selecting relays is grounded and another side is connected through resistances of equal resistance value Ro. These connecting points are connected to negative inputting terminal of a comparator 5, and at the same time, connected to a power source through a resistance Rx. Threshold value voltage is inputted to the positive inputting terminal of the comparator 5, and output is inputted to the base of a transistor Tr. The emitter of the transistor Tr is grounded and the collector is connected to the power source through a relay 4. When two or more of plural control item selecting relays operate, voltage of negative inputting terminal of the comparator 5 becomes lower than the threshold value voltage, and output of the comparator 5 is inverted and the relay 4 is operated through the transistor Tr.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Technical Field of the Invention The present invention is directed to a 11i11 ft1 device σ of a one-way supervisory control system), and a multi-selection method that prohibits control when two or more control item selection relays operate. The present invention relates to a multiple selection control prohibition circuit that can be constructed at low cost.

lbl Prior Art and Problems FIG. 1 is a circuit diagram of the main part (1:JQ) of a conventional multiple selection control prohibition circuit (AI and a circuit that returns a response signal when the control item selection relay operates).

In the figure, 1 is a mercury relay, 2 and 3 are relays, rLl-1 to r
tn-s and r4+-2 to r7n-2 are contacts of each control item selection relay (not shown), rtlo is a contact of mercury relay 1, rtil is a contact of relay 3, R11mo is a resistor, and ■ is a power supply. Indicates voltage.

When the control device side sends a signal to operate the control item selection relay on the controlled device side in accordance with the control item, the control item selection relay corresponding to this control item operates, and the contact of this control item selection relay, e.g. rl+-s.

r71-2f: Connected, operate relay 3 in Figure 4 (q), connect contact rtxt in IBI in Figure 1, operate relay 2, and send a response signal indicating that the control item selection relay has operated to the control device. In response to this, the control device sends a control signal and performs control.In this case, the control item selection relay corresponds to one control item, and two or more control item selection relays cannot operate. This is not allowed. However, due to address setting error or malfunction of the control item selection relay, two or more control item selection relays may operate.For this reason, 抛1
A multiple selection control prohibition circuit shown in FIG. 5 is used.

Figure 1: In the human circuit, one control item selection relay operates biasedly, for example, if contact rt+-1 operates, mercury relay 1 operates, and when two or more control item selection relays operate, mercury relay 1 operates. is activated, and as shown in Figure 1 (even if contact rtIo is open and contact rz++ is connected), relay 2 does not operate, indicating that the control item selection relay has operated, and does not send a response signal. Therefore, control at the time of multiple selection is prohibited. However, it must be changed depending on whether the mercury relay 1 is activated or not, and whether the resistance value of the resistor connected in series with the mercury relay 1 is 10R or R,→几/2. Therefore, the operation of normal relays becomes uncertain, so in the conventional multiple selection control inhibition circuit, a highly sensitive mercury relay with an ultimate relay structure is used to improve reliability, but it has the disadvantage of being expensive.

[C1 OBJECT OF THE INVENTION In view of the above drawbacks, an object of the present invention is to provide a multiple selection control inhibition circuit that can be constructed at low cost.

(Constitution of the Invention In order to achieve the above object, one of the contacts of a plurality of control item selection relays is grounded, the other is connected through a resistor of the same resistance value, and this connection point is connected to a comparator. The comparator is connected to the negative input terminal of the comparator and connected to the power supply via a resistor, and the threshold voltage is input to the positive input terminal of the comparator.The output is connected to the base of the transistor, and the emitter of the transistor is grounded for comparison. The voltage at the negative input terminal of the comparator becomes lower than the threshold voltage, the output of the comparator is inverted, and the relay is actuated through the transistor.

tel　Embodiments of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a multiple selection control prohibition circuit IA according to an embodiment of the present invention.
I and response signal generation circuit (a).

Components in the figure that have the same functions as those in FIG. 1 are indicated by the same symbols.

4 is a relay, rz+z is a contact of relay 4, 5 is a comparator,
Tr is a transistor, Ro, l are also x, Ry, Rz, I-
L indicates resistance.

In the circuit of Figure 2 +AI, the threshold voltage EI of the comparator 5
is expressed by the following equation.

Ry Also, when one contact of the control item selection relay is connected, the voltage E input to the negative input terminal of the comparator 5! is expressed by the following equation.

The voltage Et input to the negative input terminal of the O time comparator 5 is expressed by the following equation.

Here, select the resistance](y, Rz so that the threshold voltage E1 is an intermediate value between E and E'2.If the threshold voltage lD1 is determined as described above, the control item selection relay 1
When the contacts rt12 are in contact, the output of the comparator 5 is at a potential of approximately 0, the transistor Tr is off, no current flows through the contacts rt12, and the control item rt12 is in contact. A response signal indicating that the selection relay has been activated is sent. If only two contacts of the control item selection relay are in contact, the output of the comparator 5 is inverted and reaches a potential of approximately v■, the transistor Tr is turned on, the relay 4 is operated, and the contact rt12 is opened (!:
Therefore, no response signal is sent out indicating that the control item selection relay has operated. Therefore, control at the time of multiple selection is prohibited. Here, whether the output of the comparator 5 is approximately □V or yV is determined by the voltage input to the negative input terminal being slightly larger than the threshold voltage E1, and whether it is Ov or ■" is determined by the transistor 'vr Since the current flowing through the comparator 5.transistor/l changes greatly, relay 4 may be an ordinary relay.
Tr, resistance 1 (Y.

Even if Z and Z are taken into account, it is cheaper than the mercury relay 1 shown in FIG. 1, and the control prohibition circuits 1 and 6 at the time of multiple selection can be constructed at a low cost.

(fl　Effects of invention As described above in detail, the present invention provides a comparator.

Even when transistors and resistors are taken into consideration, it is cheaper than a mercury relay, so it has the effect of making it possible to construct a control prohibition circuit at multiple selections at a low cost.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram mainly consisting of a conventional multiple selection control prohibition circuit, and FIG. 2 is a circuit diagram mainly consisting of a multiple selection control prohibition circuit according to an embodiment of the present invention. In the figure, 1 is a mercury relay, 2 to 4 are relays, rAl-1 to r
tn-1, rtl-2 to rtn-2 are the contacts of the control item selection relay, rtlo is the contact of mercury relay 1, and rtu is 1
RZ+2 is the contact of RU-3, rz+2 is the contact of RU-4, 5 is the comparator, l1lr is the transistor, 几0 and 1 are also R,, R2
゜Rx, Ry, R2 are resistances, and V is a power supply voltage. See Figure 1 (B Figure 2)

Claims (1)

[Claims] Controlled device in remote monitoring control system ζ ℃ ℃ , each contact of multiple control item selection relay 0) One side is grounded, the other is connected through a resistor with the same resistance value, and this connection point is connected to the comparator. It is connected to the negative input terminal (connected to the power supply through the upper stake, and the comparator σ), and the positive input terminal ζ inputs the threshold f direct voltage and outputs the transistor O). ) The emitter C is grounded and the collector is connected via a relay.
! is connected to the power source, and when the plurality of control item selection relays are turned on, the voltage at the negative input terminal of the comparator becomes less than the UM value voltage, and the output of the comparator becomes A multiple selection control prohibition circuit characterized in that the relay is operated through the inverted transistor.