Mitsubishi Electric MELSEC iQ-R Series Safety Manual page 94

Entering detection and existence detection circuit 1
■Application overview
This application detects entering and existence of a person in a hazardous area and turns off the power source of a robot.
The entrance of a person to the hazardous area is detected with a light curtain. The existence of a person in the hazardous
area is detected with a laser scanner. When the entrance or existence of a person has been detected, a robot is stopped.
The robot cannot be started until the person leaves the hazardous area.
This controls the start and stop of a robot by turning on or off the main contact of the contractor which opens and closes the
power source of a robot.
Connect the light curtain, laser scanner, and electromagnetic contactors to a safety programmable controller.
The Safety CPU controls on or off of the electromagnetic contactors with program.
When the safety programmable controller detects an error with the self-diagnostics, outputs to the electromagnetic contactors
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.
After ensuring safety (the light curtain and laser scanner signals are both on), the worker shall press reset switch first.
Pressing the start switch turns on the electromagnetic contactors.
2.
When a safety electromagnetic contactor is welded, input the electromagnetic contactor (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.
The electromagnetic contactor outputs are turned off when the light curtain signal or laser scanner signal is turned off or
an error is detected in safety remote I/O module after the operation is started.
(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
92
5.1 System Configured by a Safety CPU