1794-asb Power LED off

Hello,

This seems like a dumb question, but I'm a little confused with our flex IO. When I connect the power supply all LED's (Power, Active, Adapter Fault, Local Fault) light up for a second, and then they all turn off. I can measure the input power and it's 24VDC, but the Power LED remains off. I know that in normal conditions Active, Adapter and local Faults are off, but is this the same case with the Power LED, of is it supposed to be ON as long as there is power?

I attached images of our system in case it helps get an idea. Thanks for the help!

Jose

Welcome to the Forum !

The 1794-ASB itself doesn't have an LED to indicate field power.

The only 'power' LED I see in your photos is the one on the analog module, indicating field power is present. That agrees with your measurement.

In general, the Active LED should be solid green when the adapter is being scanned by the 1756-DHRIO, and flashing green when it's being scanned by the controller is in PROG mode which consequently puts the -ASB in Idle mode).

Are you (re-)commissioning this system for the first time, or trying to investigate a fault ?

The red BAT LED on the ControlLogix is worrisome... if you don't have a nonvolatile version of the 1756-L55, you are one power cycle away from losing the user program.

Ken,
Thanks for the reply. We are trying to figure out the fault with our system. It's hardly noticeable, but the Touchscreen display indicates that there is a communication error.

We were hoping that it was just the power in the Flex IO, but now it seems that we might have lost the program... We did experience a power outage recently and shortly after that we lost communication with the system.

If you know anything else, please let me know. If not, we might just go with this and try and get the program back. Also to get the battery fault fixed.
Thanks for the help,

Jose

Is the system still under control ? The user program is either gone, or it isn't; there are no half-measures there.

Unless you have RSLogix 5000 software and a basic idea of how to go online and use it, the safest thing is to call an integrator or consultant who does, so they can carefully go online and determine if there is an existing program or a nonvolatile memory module.

Thanks for the help. It was that we lost the program when we had the outage. We downloaded the program again and we are going to replace the battery. Now it's working better.

Thanks!

Jose