Two-Hand Operation Switch - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

5
SAFETY APPLICATION CONFIGURATION EXAMPLE (USING A
SINGLE SAFETY PROGRAMMABLE CONTROLLER)
5.6.8

Two-hand operation switch

(1) Application overview
This application prevents a worker from approaching to hazardous area by energizing
a robot only when two buttons are simultaneously activated with both hands.
A press machine that starts sliding by activating two buttons is the typical application
example.
Start and stop of the robot is controlled with contactors that close and open the power
supply.
Connect the two-hand operation switch and contactors to a safety programmable
controller.
The safety programmable controller turns on/off the main contacts of the contactors
with a sequence program.
When the safety programmable controller detects an error by self-diagnostics, outputs
to the contactors 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.
(Partially quoted from "Safety Guide Book - the safety measures of machinery in the workplace"
: Nippon Electric Control Equipment Industries Association.)
1) After ensuring safety, activate the two buttons on the two-hand operation
switch. The contactors turn on only when timing when the buttons are
activated is within 500ms difference.
2) When the main contacts of the contactors are welded, do not start the
robot. Input the auxiliary contacts (normally closed contacts) to the safety
programmable controller to check for welding.
3) When one or both of the hands are released from the buttons or an error is
detected in the safety remote I/O station on CC-Link Safety after
operation, outputs to the contactors turn off.
Figure 5.62 Two-hand operation switch
5.6 Case Examples
5.6.8 Two-hand operation switch
1
2
3
4
5
6
5
- 76