CompactlogixL43 Does not see some modules missing

[terry56]

Hey Guys,
I have a CompactLogix L43 system. The first 1769-PA4 Power Supply has 6 Digital I/O modules, mounted to the CompactLogix and the next 4 Analog I/O modules are mounted via a second 1769-PA2 Power Supply.

Everything is working OK, but if I shut off the second Power supply (1769-PA2) I was expecting an I/O error of some sort. I get Analog "problems" but no Module Faults.

Any Ideas??

 

[jeffsnyder]

Do you have a right end cap terminator installed?
Do you have both power supplies installed without a left-to-right cable installed between them?

 

[terry56]

Yes, I have an ECR fitted and Yes, I have a left-to-right cable installed.