ControlLogix Online Indicators

Why is the I/O indicator flashing green when I am monitoring the program online in ControlLogix

At least one of the I/O connections is not available. This, at least in this configuration, is not enough to prevent it going into 'Run' mode or causing a fault, but the equipment may not operate fully. Look at the status icons in the I/O configuration for the problem items.

That can also happen if you have a communications module listed in the I/O tree, with nothing connected to it in the I/O tree. The usual culprit here is the Ethernet module. There is no reason to list it in the I/O tree unless you are using it for remote I/O or produced/consumed tags.

If it is listed, with no partner, it will give the blinky I/O light warning.

The I/O light will also flash if you have Consumed tags that are not being consumed (e.g. the producer is not there, or there is a configuration error).

Look in the I/O Configuration area of the controller organiser, and follow the warning triangles to the module that is in error, double-click it to bring up the Properties dialog, then choose the "Connection" tab. On there you will see what the fault is.

rdrast said:

That can also happen if you have a communications module listed in the I/O tree, with nothing connected to it in the I/O tree. The usual culprit here is the Ethernet module. There is no reason to list it in the I/O tree unless you are using it for remote I/O or produced/consumed tags.

If it is listed, with no partner, it will give the blinky I/O light warning.

Click to expand...

I've never seen that happen... Which comms module(s) is this relevant to?

I've just tried it with an ENBT in the configuration, with no children, and no I/O errors are present.

daba said:

I've never seen that happen... Which comms module(s) is this relevant to?

I've just tried it with an ENBT in the configuration, with no children, and no I/O errors are present.

Click to expand...

If there is a 1756-DHRIO included in the I/O tree and is used only for DH+ it will cause the I/O light to blink.