JPH0496802A - I/o unit device - Google Patents

Abstract

PURPOSE:To reduce the space and the cost by switching a main output circuit to an auxiliary output circuit to output the output of the auxiliary output circuit at the time of abnormality of the output of the main output circuit and continuously supplying a signal to a load. CONSTITUTION:In an I/O unit, a signal obtained by converting the level of an output terminal 6 into an internal logic level by a level converting circuit 3 and an output signal OUT of a CPU unit are always compared with each other by a gate circuit 4, and the output is judged to be faulty to invert the Q output of a flip flop 9 if they do not coincide with each other for a certain time or longer. Consequently, the Q output of the flip flop 9 is switched from the low level to the high level, and the Q output is switched from the high level to the low level, and the output of an auxiliary output circuit 2B is turned on/off by the output signal OUT. Thus, the cost is reduced, and the space occupied by the circuit is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to an I/O device used in a programmable controller.
It concerns a 10 unit device.

[Prior art] Fig. 2 shows a conventional example, in which each independent I10 unit A
, B are provided, and each logic circuit unit 1 is provided with a CPU
The same signal is fed from the unit, and the logic circuit section 1
．． 1 does the same thing. Also.

■ 0 units A and B are each photocouplers pr
:', relay Ry1. It is composed of an output circuit 2 consisting of a relay connection, a diode r, etc., a level conversion circuit 3, a gate circuit 4, a timer F1B 5, etc. Contact r, which is an output contact, is connected to the output terminal, and both I,,'r)
Output terminals C1 of units A and B are commonly connected externally,
The output end 6 has a p load 1. and a power source 7 are connected.

In both I ′0 units A and H, initially! , 0 unit A is selected, and I from the output switching control circuit 8 is selected.
The logic circuit section l is controlled by the 'Ouni IA output permission signal, and the output is CP LJ.
The output circuit 2 is turned on and off by a control signal from the unit. In this case, normal operation signals indicating whether or not the operation of each I70 unit A and B is normal are inputted to each other by being connected to each other by external wiring. In addition, the level conversion circuit 3
converts the state of contact r to a logic level, and compares its output with the output of logic circuit section l in gate circuit 4, and if they do not match for a certain period of time, the timer circuit 5 outputs a normal operation signal and an abnormal signal as an off signal.

In this state, the operation when the output of I10 unit A fails is as follows. First, the self output (contact r output) and the output of the 50 thick circuit section 1 are monitored by a level conversion circuit 3, a gate circuit 4, a timer circuit 5, etc. (not shown), and if a mismatch is detected for a certain period of time or more, Turn off the normal operation signal output. At the same time, cut off the output of its own i10 Uni Soto A. This interruption is performed by turning off the I/'O unit output permission signal.

■／'0 Monitoring the normal operation signal of unit A■
/'0 Unit B changes its own output permission signal from OFF to ON state by this signal, and outputs CP I to output port #I2.
Outputs the contact signal from the J unit. In other words, I10
If unit A fails, the output of contact r of the other I/'O unit B will be supplied to the load. With this method, the output circuit of the I/O unit can be duplicated.

[Problem to be solved by the invention] In such a conventional example, when this method is used, the main
'0 unit and auxiliary 1. , 'The user must externally connect each output of the O unit, which is time consuming. Furthermore, since two identical I,'0 units A and B are required, duplication requires twice as much space and cost as compared to the case of output car weight, which is not efficient.

The present invention has been provided in view of the above-mentioned points, and an object of the present invention is to provide a 17'0 uni-node device in which the wiring is the same as that of a normal I10 unit, and the space and cost are less than twice as large. That is.

[Means for Solving the Problems] The present invention includes a main output circuit and an auxiliary output circuit that output the same output to one output terminal, and when the output of the main output circuit is abnormal, the output is switched from the auxiliary output circuit. It is equipped with a control means for controlling the

[Function] Therefore, when the output of the main output circuit is abnormal, the control means switches to the auxiliary output circuit to output the output, and the output terminal f! :
rr and continue outputting the signal j, - to the 0 load.

[Example] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Generally speaking, when a programmable controller is used, output circuit failures are considered to be due to contact failures, if any.

In addition, the transistor output field a may be caused by transistor breakdown due to load overcurrent or the like, or accompanying photocoupler breakdown. From the point 2J), there is a very small possibility that the internal logic/12 circuit section will fail, and there is no advantage to duplicating it.

Therefore, in the present invention, there is only one logic circuit section and only the output circuit is duplicated. Connect the output circuit to the main output circuit lN2
A and auxiliary output circuit 2B.

Further, the output of the gate circuit 4 is integrated by a CR integrating circuit 10 consisting of a resistor R and a capacitor C, and the output is inputted to a free knob flop 9, and the Q output and the Q output are respectively acidified ++, , (-; 2. Manpower is required.

And K) +-;,, +-,, output from main output circuit li+82A and auxiliary output port FI? 12R requires 1-manpower.

In the initial state, etc., the Q output power of Furi I Afronopuri - level J), so when the output signal from I'F' Ll Unirid is OL+ 1' or L level, the main output circuit 2A
f) Output turns on. ′), and due to the movement of the main output circuit g 2 A), the externally connected load [, , becomes active. It is best to connect the second load [- to the output terminal 6 of 1-) in the same way as the normal 1-0 unit node, and to double the I/O unit and connect it in parallel.
9 At this time, the signal obtained by converting the level of the output terminal CI to the internal four-way level by the level conversion circuit 3, and CP (1 The gate circuit 4 constantly compares the output r with the number 0 [I let

The second constant time is +1. during fil- when the output signal OUT changes. 11th grade in junior high school
#Declaration (This is the time until it becomes 1'. Within this time, the flip-flop 9 will not be inverted by the CR integration circuit 10.

Due to this fault occurrence, the Q output of flip-flop 9 becomes low.
level to H level, the Q output changes from H level to L level, and from then on, the output of the auxiliary output circuit 2B is the output signal OU.
It is turned on and off by T. This output switching causes a warning signal to be generated to the CP unit. In addition, level conversion circuit 3, gate circuit 4, CF5 integration circuit 10, flip 70 tube 9
etc. constitute the control means.

[Effects of the Invention] As described above, the present invention includes a main output circuit and an auxiliary output circuit that output the same output to one output terminal, and when the output of the main output circuit is abnormal, the output is output from the auxiliary output circuit. Since it is equipped with a control means for switching and outputting, when the output of the main output circuit is abnormal, the control means switches to the auxiliary output circuit and outputs the output, so that the signal is continuously output to the load via the output terminal. There is something that is there, its name, 1
With two output terminals, the external wiring can be made exactly the same as a normal 1/'O uni-soto, and since the internal logic circuits other than the main output circuit and auxiliary output circuit are common, it is compared to the conventional one. This has the advantage that the cost is low and the space occupied by the circuit is small.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, and Fig. 2 [2I] is a circuit diagram of a conventional example. 2A is a main output circuit, 2B is an auxiliary output circuit, 6 is an output terminal, and L is a load. Agent Patent Attorney Ishi 1) Chief 1st v! J 2A Main output circuit 2B Auxiliary 7J times 18 t, -IXt) End Y- 8 Clause 2nd B

Claims (1)

[Claims] (1) In an I/O unit device that receives a signal from a CPU unit and outputs the signal to an output terminal to control a load, a main output circuit and an auxiliary output circuit that output the same output to one output terminal An I/O unit device comprising: control means for switching and outputting an output from an auxiliary output circuit when the output of the main output circuit is abnormal.