Mitsubishi Electric MELSEC iQ-R Series Safety Manual page 88

Guard monitoring circuit
■Safety application overview
This application de-energizes a robot with the safety switch on the guard of a safety barrier when the guard is opened.
The robot cannot be started while the guard of 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 CPU controls on or off of
the safety relays with program.
When the safety programmable controller detects an error with the self-diagnostics, outputs to the safety relays turn off
independent of the program.
In this case, regardless of the program, the outputs remain off until the Safety CPU or safety remote I/O module is reset.
Configure the program so that the following functions can be achieved.
1.
Check that safety is ensured (the emergency stop signal is on state). Then, the worker presses the reset switch first.
Pressing the start switch turns on the safety relays.
2.
When a safety relay is welded, input the safety relay (normally closed contact) to the safety programmable controller to
prevent starting, and check for welding.
3.
To avoid undesired operation of the reset switch and start switch at welding or short-circuit, set the reset switch and start
switch so that they are activated only when turned on and off.
4.
When the safety barrier 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 module after operation starts, outputs to the safety relays turn off.
(Partially quoted from "Safety Guide Book - the safety measures of machinery in the workplace": Nippon Electric Control
Equipment Industries Association)
5 SAFETY APPLICATION CONFIGURATION EXAMPLES
86
5.1 System Configured by a Safety CPU