Case Examples - Mitsubishi Electric MELSEC iQ-R Series Safety Manual

Case examples

Emergency stop circuit (stop of the entire equipment)
■Application overview
This application uses a safety programmable controller in each process and cuts off a power to robots in all processes using
an emergency stop switch in any process.
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 at the safety relay contact.
Connect emergency stop switches and safety relays to safety programmable controllers.
Connect Safety CPUs installed to each process with CC-Link IE Field Network. 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) and that an emergency stop request is not received
from another Safety CPU on CC-Link IE Field Network. The worker shall press the reset switch first. Pressing the start
switch turns on the safety relays.
2.
When a safety relay connected to the safety programmable controllers 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.
Outputs of the safety relays turn off when input of the emergency stop switch turns off, an emergency stop request is
received from another Safety CPU on CC-Link IE Field Network, or an error is detected in a safety remote I/O module
after the operation is started.
5.
To stop the entire system, transfer the emergency stop request to other Safety CPUs.
(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
174
5.2 System to Which Multiple Safety CPUs are Connected