Controller Fails to Stay in Auto Mode (Cascade), Keeps Reverting to Manual Mode.

Sounds like somebody does not have sound software.

It sounds as though human intervention is required. Is this thing a self-contained proprietary unit, Boss? If so, then a telephone call to the manufacturer would be first intervention I would make. Then, I'm funny that way.

Whoever might know the answer would need to know the manufacturer and model, at least. Surely you have a manual available?

I use delta V and i get this message MODBAD.

A change in velocity will have very little effect on any imaginary number. If your module is bad then fix or replace it. That is what I would do.

[Punctuation, capitalization and proper syntax is very important for precise communication.]

The "MODBAD" error in a DELTA V DCS indicates at least one module in the system is bad and requires replacement.

Be aware that there may be more than one module that has failed.

You need to go to the engineering node/terminal and drill down through the fault table to identify which modules are bad and replace all that are listed as "bad".

If you are not comfortable with performing this operation contact the DELTA V technical support for advice and follow their directions.

Look at all the things it could be (discussion on LinkedIN)

https://www.linkedin.com/grp/post/1270757-210891384

Thank you for the link

Sounds like human intervention, with trouble shooting abilities, is required.

This fault can't be fixed over the internet.

Sounds like the default mode is working correctly.

This could also be a simple case of ESO.

Do you have access to the signal diagram? If you do, you can bring the signal diagram up for troubleshooting purposes. It should give enough information (provided you can understand the logic blocks well enough to determine the cause). In many cases modules or level transmitters will give a Bad Quality indication which will automatically cause the unit to fail to a manual reject state. Determine if this is the case and you should also be able to determine which module or transmitter is bad quality.

What software are you using? (e.g. Emerson, etc.?)

Hi

Seems Ur DCS controller configuration is such a way, your controller configuration enabled to Setpoint track mode. That means when ever any failure of input value from field & any interruption is communication makes the set point tracks the measured mode. Pl check for SP track option in your DCS controller configuration.