Case Examples; Emergency Stop Circuit - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

5
SAFETY APPLICATION CONFIGURATION EXAMPLE (USING A
SINGLE SAFETY PROGRAMMABLE CONTROLLER)
5.6

Case Examples

5.6.1

Emergency stop circuit

(1) Application overview
The emergency stop circuit is the safety application that turns off the power source of
a robot with the emergency stop switch.
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 emergency stop 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 emergency stop signal 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) The safety relay outputs are turned off when the emergency stop switch
input is turned off or an error is detected in the safety remote I/O station on
CC-Link Safety after the operation is started.
Figure 5.6 Emergency stop switch
5.6 Case Examples
5.6.1 Emergency stop circuit
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