Hi,
I'm looking at a newish system we have on site and noticed they are resetting the Pilz safety PLC via ethernet comms from the main Siemens PLC. The reset button is wired to the Siemens PLC and then passed through over profinet.
This seems a bit risky to me. It's used to reset the E-stop Pilz block, which is set to manual on a positive edge trigger, but I'm surprised that Pilz even allow this to be used for the reset?
Is there anything wrong with doing this, and if so does it break any of the safety regulations?
I found this thread: http://www.plctalk.net/qanda/showthread.php?t=65761
…which talks more about using a PLC output as the reset of a safety relay. That doesn't sound as bad as using communications, as we all know these call fail in many different ways, hence the use of a watchdog / tick-tock monitor.
Thanks
Russ
I'm looking at a newish system we have on site and noticed they are resetting the Pilz safety PLC via ethernet comms from the main Siemens PLC. The reset button is wired to the Siemens PLC and then passed through over profinet.
This seems a bit risky to me. It's used to reset the E-stop Pilz block, which is set to manual on a positive edge trigger, but I'm surprised that Pilz even allow this to be used for the reset?
Is there anything wrong with doing this, and if so does it break any of the safety regulations?
I found this thread: http://www.plctalk.net/qanda/showthread.php?t=65761
…which talks more about using a PLC output as the reset of a safety relay. That doesn't sound as bad as using communications, as we all know these call fail in many different ways, hence the use of a watchdog / tick-tock monitor.
Thanks
Russ