Mitsubishi Electric MELSEC iQ-R Series Safety Manual page 191

Entering detection and existence detection circuit 1
■Application overview
This application uses a safety programmable controller in each process and detect the entrance 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.
Connect Safety CPUs installed to each process with CC-Link IE Field Network. 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.
Check that safety is ensured (both of the light curtain and laser scanner signal are turned on) and when the entrance and
existence of a person in a hazardous area is not detected by another Safety CPU on CC-Link IE Field Network, the
worker shall press the reset switch first. Pressing the start switch turns on the electromagnetic contactors.
2.
When an electromagnetic contactor connected to the safety programmable controller installed to the processes 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.
Turn off the outputs of electromagnetic contactor, when light curtain signal or laser scanner signal is turned off after
operation starts, when the entrance and existence in a hazardous area is detected by another Safety CPU on CC-Link IE
Field Network, or when an error is detected on safety remote I/O module is detected.
5.
To stop the entire system, transfer the emergency stop request to other Safety CPUs.
*1
*1 There is no guard between the processes. There is no barrier between the processes.
(Partially quoted from "Safety Guide Book - the safety measures of machinery in the workplace": Nippon Electric Control
Equipment Industries Association)
*1
5 SAFETY APPLICATION CONFIGURATION EXAMPLES
5.2 System to Which Multiple Safety CPUs are Connected
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