Case Example; Emergency Stop Circuit (Stop Of All Equipment) - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

6
SAFETY APPLICATION CONFIGURATION EXAMPLE (USING
SEVERAL SAFETY PROGRAMMABLE CONTROLLERS)
6.4

Case Example

6.4.1
(1) Application overview
6
- 8 6.4 Case Example

6.4.1 Emergency stop circuit (stop of all equipment)

Emergency stop circuit (stop of all equipment)
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.
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 emergency stop switches and safety relays to safety programmable
controllers.
Connect safety programmable controllers in all processes through CC-Link IE Field Network.
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.
1) Check that safety is ensured (The emergency stop signal is on.) and that
an emergency stop request is not received from another safety
programmable controllers on CC-Link IE Field Network. Press the reset
switch and the start switch. The safety relay will turn on.
2) When a safety relay connected to any safety programmable controller is
welded, input the auxiliary relays (normally closed contacts) to the safety
programmable controller to prevent start of the robots, and 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) 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 programmable controller on CC-Link IE Field Network, or an error is
detected in a safety remote I/O station on CC-Link Safety after the
operation is started.
5) To stop the entire system, transfer the emergency stop request to other
safety programmable controllers.
Figure 6.3 Emergency stop circuit (stop of all equipment)
(Partially quoted from "Safety Guide Book - the safety measures of machinery in the workplace"
: Nippon Electric Control Equipment Industries Association.)