F
For an industrial gas turbine application, should you require an independent watchdog for a ControlLogix PLC?
I'm used to seeing independent Watchdogs on an E-Stop loop for control systems. For example, the Mark II had re-triggerable relays that the processor needed to set every few milliseconds or the E-stop loop would be opened. It did processor to processor calculations to verify network communications as well.
I keep hearing "ControlLogix" has built in watchdogs, but I don't understand how something can truly monitor itself, and I don't see any special watchdog outputs on the processors. If the processor "freezes" how can it take action if it's the thing frozen?
Agree? Disagree? Does anyone know of any Rockwell Literature supporting this claim?
Thanks for you input.
-Frank
I'm used to seeing independent Watchdogs on an E-Stop loop for control systems. For example, the Mark II had re-triggerable relays that the processor needed to set every few milliseconds or the E-stop loop would be opened. It did processor to processor calculations to verify network communications as well.
I keep hearing "ControlLogix" has built in watchdogs, but I don't understand how something can truly monitor itself, and I don't see any special watchdog outputs on the processors. If the processor "freezes" how can it take action if it's the thing frozen?
Agree? Disagree? Does anyone know of any Rockwell Literature supporting this claim?
Thanks for you input.
-Frank