Hi everyone,
I'm having a little problem, whenever I connect BCKAL_OUT from AO block back into PID BCKAL_IN, my PID's Actual mode gets stuck in IMAN mode and I cannot seem to bring it back into AUTO or MANUAL for that matter.
Its a simple feedback loop loop in a direct acting controller.
Is the AO block target and actual mode in "CAS"? If that is in Auto or MAN then you would get an IMAN on the PID.
What mode is the ao block in? If it is not in Cas then the pid will not get out of iman. saroche <bounce-saroche@community.emerson.com> wrote:
The AO block TARGET mode is not in CAS, or the block is unable to go to CAS because the channel is BAD, preventing the block's ACTUAL mode from going to CAS.
THe BCKAL signal initiates a Cascade Requested signal to the PID when the AO block is placed in CAS mode. However, if the block has an issue, the status back to the PID may be BAD rather than GOOD CASCADE. In that case, you have to clear the source of the issue in the AO block before it can request cascade.
What is the Status at the PID/BCKAL_IN, including the substatus? This will tell you what the AO is instructing and reflect if a BAD status or the CAS request message is present.
Andre Dicaire
In reply to mikesteiger:
Sorry Mike, I put my question wrong altogether, its already night here and I'm not concentrating!! :(
Its the AO block thats in IMAN actual mode, not the PID..
Is it because of physical disconnection from the field, because currently there's no field device connected but i'm trying to make it work.
In reply to saroche:
So there is no field device hooked up to the AO block or the PID?
The device physically is not connected to the AO module, but a channel is configured on the AO block.
I might not be the right person to answer this question, I typically only work with Fieldbus devices and my knowledge about traditional channels is limited. I don't know if you will be able to get it to go into CAS without being attached to a device. I think there would be a bad status for the AO block.
When you look at the BKCAL_OUT value in Control Studio Online, what is the status of that value? It sounds like the AO block is saying that it will not accept an output from the PID block. The AO block could be in the wrong mode, be output limited, or any number of factors.
Gareld Butler
In reply to Scott Thompson:
I thought you could also not assign a card and channel to the AO block and it would not give you the Iman error.