Entering Detection And Existence Detection Circuit 2 - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

5
SAFETY APPLICATION CONFIGURATION EXAMPLE (USING A
SINGLE SAFETY PROGRAMMABLE CONTROLLER)
5.6.4
(1) Application overview
5
5.6 Case Examples
- 39

5.6.4 Entering detection and existence detection circuit 2

Entering detection and existence detection circuit 2
The entering detection and existence detection circuit is the safety application that
detects the entrance and existence of a human in a hazardous area and turns off the
power source of a robot.
The entrance of human to the hazardous area is detected with a light shielding of the
light curtain. The existence of human in the hazardous area is detected with mat
switch. When the entrance or existence of human has been detected, a robot is
stopped.
The robot cannot be started until the human leaves the hazardous area.
Start and stop of the robot is controlled with contactors that close and open the power
supply.
The safety programmable controller turns on/off the main contacts of the contactors
with sequence program.
Connect the light curtain and contactors to a safety programmable controller.
The relay is connected between the mat switch and safety programmable controller.
The safety programmable controller turns on/off the main contacts of the contactors
with 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.
1) After ensuring safety (The light curtain and mat switch signals are both
on.), activating the reset switch and then the start switch turns on the
contactors.
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) The reset switch and start switch become valid only when turned off to
avoid operation at contact welding or short-circuit.
4) The contactor output is turned off when the light curtain signal or the relay
input of mat switch is turned off or an error is detected in the safety
remote I/O station on CC-Link Safety after the start.