JPH0586013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a selection relay output circuit that obtains a contact output according to an encoded selection signal.

A conventional circuit of this type is shown in FIG. 1 or 2. In FIG. 1, a decoder 1 decodes an encoded selection signal and a corresponding selection relay 2 ₁
Drive at least one relay 2 ₁ ~ _{2 o}
Each contact 3 ₁ to 3 _o is the common terminal COM and output terminal
Connected to OUT ₁ to OUT _o and taken out as contact output. In this circuit, in order to increase the contact output capacity (current breaking capacity), it is possible to use a relay with a large contact capacity for each relay.
The larger size of the relay itself creates problems in terms of mounting space and cost.

In Fig. 2, the contact ₄₁ of the power relay 4 with a large contact capacity is provided as a common output contact between the contacts ₃₁ to _{3o of each relay 21 to 2o and the} common terminal COM, and the drive of this relay 4 is controlled by timing. The circuit 5 is configured to control the timing shown in FIG.
That is, the timing circuit 5 receives the timing of the selection signal from the decoder 1 and sends it to the selection relays ₂₁ to _2o.
The relay 4 is driven to close the contact 4 ₁ after the contact closes, and conversely, the relay 4 is driven to open the contact 4 ₁ before the selection relay opens, and the output current is opened and closed by the contact 4 of the relay 4. By burdening ₁ ,
For the selection relays 2 ₁ to 2 _o , it is possible to use relays with a small current breaking capacity at their contacts.

However, in the circuit shown in FIG. 2, the timing circuit 5 requires a large number of auxiliary relays and timers, making the circuit complicated, and readjustment is required in accordance with changes in the timing relationship between the selection code and the selection relay. It is inferior in _versatility , as it requires a

SUMMARY OF THE INVENTION An object of the present invention is to provide a selection relay output circuit in which the operating timings of a power relay and a selection relay can be reliably changed and easily changed.

The present invention is characterized in that the control of the power relay and the selection relay is programmed by a microcomputer, and the control timing and whether or not to perform processing are determined by taking in contact operation data from the auxiliary contact state of each relay.

FIG. 4 is a circuit configuration diagram showing an embodiment of the present invention. Power relay 4 and selection relays 2 ₁ to 2 _o are connected with contact 4 ₁ as a common output contact and contacts 3 ₁ to 3 _o as selection output contacts. power relay 4
The selection relays 2 ₁ to 2 _o are driven as respective channel outputs of the digital output circuit 7 of the microcomputer 6. In addition, the power relay 4 and the selection relays 2 ₁ to 2 _o are connected to auxiliary contacts 8 ₁ and 9 ₁ to 9 _o, respectively.
The contact ₈₁ is connected alone, and the contacts ₉₁ to _9o are connected in parallel to the digital input circuit 1 of the microcomputer 6.
0, and the state of each contact, that is, the operating state of the relays 4, _{2 1} to 2 _o , is taken in as an on/off signal. Digital input circuit 10 also includes a channel for receiving selection signals. The microcomputer 6 has a digital output circuit 7 and an input circuit 1.
0 is bus-coupled with the CPU 11 and memory 12,
The CPU 11 selects and controls the relays ₂₁ to _2o corresponding to the selection signal according to the program in the memory 12,
The timing control of the power relay 4 and the state data of the auxiliary contacts 8 ₁ , 9 ₁ to 9 _o of each relay are incorporated into the control.

The control mode of the microcomputer 6 will be explained below with reference to the time chart of FIG.

The selection signal (t ₁ in FIG. 3) taken in through the digital input circuit 10 is compared with the code assigned to each selection relay 2 ₁ to 2 _o in the CPU 11 to determine the selected relay (decoding function). next,
A channel output corresponding to the selected relay is outputted from the digital output circuit 7, and the selected relay is driven. By driving this selection relay, the change in the contact state is input to the CPU 11 through the input circuit 10 (time t ₂ ), and from this data
The CPU 11 connects to the power relay 4 through the output circuit 7.
control the drive. When the contact ₄₁ of the power relay 4 is on _, the contact of the selected relay is already closed, and when the contact of the relay 4 is on (time _t3 ), _the external You can get the output.

Next, when the selection signal is stopped (time t ₄ ),
The CPU 11 first stops driving the power relay 4,
It is determined from the state of the auxiliary contact 8 ₁ that the contact 4 ₁ of the power relay 4 is open, and the selected relay is stopped (time t ₃ ). Therefore, when the contact of the power relay 4 is open (time t ₆ ), the contact of the selection relay is still closed, and the external output by the power relay is cut off.

Therefore, according to the present invention, a power relay contact connected in series is provided in common to the contacts of the selection relay, and the external output is opened and closed by opening and closing the power relay contact, and the contact of the selection relay is used to select the external output. In the relay output circuit, the drive conditions and timing processing of the power relay and selection relay are obtained from the states of the auxiliary contacts of the power relay and selection relay, so a simple program can be used to control with reliable timing. Furthermore, when the microcomputer functions as a control center of an external output target device, it is provided with relay control and decoding functions as part of its functions, thereby eliminating the need for a special control means for the relay output circuit.

In the embodiment, the auxiliary contacts of the selection relays are connected in parallel and used as a common input, but a configuration in which the auxiliary contact state data is individually taken in enables more accurate control.

[Brief explanation of the drawing]

1 and 2 are conventional selection relay output circuit diagrams, FIG. 3 is a time chart in FIGS. 2 and 4, and FIG. 4 is a circuit diagram showing an embodiment of the present invention. 2 ₁ , 2 ₂ , 2 _o ... selection relay, 4 ... power relay, 6 ... microcomputer, 7 ... digital output circuit, 8 ₁ ... power relay auxiliary contact, 9 ₁ , 9 ₂ , 9 _o ...Selection relay auxiliary contact,
10...Digital input circuit, 11...CPU,
12...Memory.

Claims (1)

[Claims] 1. In a selection relay output circuit that drives at least one of a plurality of selection relays in response to a coded selection signal and obtains the contact output of the selection relay as an external output, the selection relay is commonly connected in series to each contact of the selection relay. The microcomputer includes a power relay having large-capacity contacts, an output circuit capable of driving the power relay and the selection relay, and an input circuit capable of inputting operating states of the auxiliary contacts of the power relay and the selection relay. The computer selectively drives and stops driving the selection relay in response to the encoded selection signal, and controls the power relay to drive within this driving time based on the operating state of the auxiliary contact. Selective relay output circuit.