INSTALLATION INSTRUCTIONS
EPT031055 Issue 2 September 2017 2-49
Safety control flow:
The guard doors and the shutter are monitored by the certified
programmable safety relay PNOZ mmOp from Pilz. If the system is working
correctly, the shutter will be closed when the guard door is opened.
The guard door is secured by means of 2 independent switches, giving the
system a level of built in redundancy.
The shutter is monitored by two light barriers to indicate the “open” and
“closed” state.
The shutter is opened by the shutter coil and closed by a spring. The coil is
driven by a safety output with pulsed energy. This allows a permanent
monitoring of the shutter control output by the safety relay.
The safety relay mmOp drives 2 relays on the control board by means of a
pulsed safety output.
Safety function:
The main function to bring the laser into a safe state is de-energizing of the
laser source.
In systems with shutter the laser safety is guaranteed by means of the
following four measures:
• Closing the shutter
• Switching off the laser modulation
• Disabling the laser
• Switching off the laser power.
When the guard door is opened the modulation in the controller is switched
off with a delay shorter than 10ms. An internal timer checks the switching of
the “open” and “closed” light barrier of the shutter. If both light barriers are
switched inside of 180ms (shutter close verification time), the system is
working correctly. If the time is exceeded without switching of both barriers,
or if an error status is detected (for example a fault of one light barrier), the
safety relay mmOp switches off the relays on the control board. These
relays open the interlocks 1 and 2 of the safety relay PNOZ S4 and the laser
will be disabled. The laser radiation will be stopped with a delay shorter
than 10ms. The message “Laser E-Stop” is shown on the screen.
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