Door Monitor Circuit - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

5
SAFETY APPLICATION CONFIGURATION EXAMPLE (USING A
SINGLE SAFETY PROGRAMMABLE CONTROLLER)
5.6.2

Door monitor circuit

(1) Application overview
This application de-energizes a robot with the safety switch on the door of a safety
barrier when the door is opened.
The robot cannot be started while the door on the safety barrier is open.
The application controls the start and stop of a robot by turning on or off the main
contact of the contactor which opens and closes the power source of a robot at the
safety relay contact.
Connect the safety switch and safety relays to a safety programmable controller.
The safety programmable controller turns on/off the contacts of the safety relays with
sequence program.
When the safety programmable controller detects an error by self-diagnostics, outputs
to the safety relays turn off independent of the sequence program.
In this case, the outputs remain off until the safety CPU module or CC-Link Safety
remote I/O module is reset independent of the sequence program.
Configure the sequence program so that the following functions can be achieved.
(Partially quoted from "Safety Guide Book - the safety measures of machinery in the workplace"
: Nippon Electric Control Equipment Industries Association.)
1) After ensuring safety (The safety switch is on.), activating the reset switch
and then the start switch turns on the safety relays.
2) When the contacts of the safety relays are welded, do not start the robot.
Input the auxiliary relays (normally closed contacts) to the safety
programmable controller to check for welding.
3) The reset switch and start switch become valid only when turned off to
avoid operation at contact welding or short-circuit.
4) When the safety barrier door is opened and the safety switch is turned off
or the stop switch is activated, outputs to the safety relays turn off.
5) When an error is detected in the safety remote I/O station on CC-Link
Safety after operation, outputs to the safety relays turn off.
Figure 5.14 Door monitor circuit
5.6 Case Examples
5.6.2 Door monitor circuit
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