ConrolLogix 1756-L71-Allen Bradley

Hello Everybody,

Can any one of you share the power off & power-on procedure for 1756-L71 by ALLEN BRADLEY?
We are using ControlLogix 1756-L71 with PS Unit 1756-PA72C
This must be a trick question ?!

A PLC must perform safely, correctly and predictable under any possible scenarios..the L71 is no exception.

Removing power from the PA72 will cause the CPU to perform an orderly shutdown before the DC supplies collapse - and does this in the order of milliseconds. Restoring power to the PA72 brings the L71 back to life where it performs numerous self-checks. If the PLC was in run mode when shutdown, it will go back into run mode and continue operations.

It is possible to run a programme on start up if required - I’ve found certain processes use bistable pneumatic valves where the valve ‘remembers’ it’s last position. Sometimes it’s useful to put them back into a position where you want them before continuing any process.