I am working on getting a test station setup for people at my company to play around with.
I have a DVC6200 Fischer control valve connected to the system via analog input (M-series input card and controller) which we are trying to automate in some sense. The valve does have power and air, and the control wiring appears to be correct (we are able to connect to the valve in AMS Device Manager and Valve Link and stroke it, etc).
But when we configure in DeltaV 12.3 we are having problems. We made a new control module, assigned it to the controller, and then added an AO block, referencing the actual channel that the valve is on. When we downloaded and went online, we couldn't get the block to go into any mode besides IMAN, and we are unable to drive the output.
We also tried linking to a PID block with a simulated input (planning on putting it in Manual mode and driving the output anyways), and the same thing happened-- all blocks are stuck in IMAN and we can't control.
I know I'm missing something stupid here... any help would be appreciated.
Thanks
The upstream block of a cascade pair is put into this mode when its downstream partner is in a non-cascade mode.
Is it the PID block or the AO block that got stuck in IMAN? Can you check through Diagnostics if the control valve connected to an AO channel is good?
In reply to David Asuncion:
Have you followed the guidance in the following BOL articles:
www3.emersonprocess.com/.../c_dv_fieldbus_fbs_in_control_strategy.html
www3.emersonprocess.com/.../c_fieldbus_control_strategy_procedures.html
This article specifically addressed PID stuck in IMAN:
www3.emersonprocess.com/.../c_pid_fb_block_mode_stuck_in_iman.html
In general when I have this problem, the device itself is not configured to allow CAS or AUTO as a permitted mode (per configuration seen in AMS). Start with an AO shadow block with no cascaded input and in MAN and go from there.
Both of the blocks were stuck in IMAN. I set the AO clock target mode to CAS and the PID block target mode to MAN. But they both stayed in IMAN.
In reply to depthcharge623:
Have you connected the BKCAL_OUT of the AO block to the BKCAL_IN of the PID to close the loop?
I know that you mentioned that you had a controller. Did you assign the control module to the controller or your pro+? Sometimes they lock into IMAN I think if you assign them to a Pro+
In reply to scottjturner:
You are correct Scott. If a PID block is assigned to a virtual controller (Pro+ or App Station) it would be lock into IMAN. Virtual controllers doesn't support control strategy execution that's why it won't allow you to put the PID in AUTO mode.
Youssef--
Can't click on those links... having trouble logging into Guardian account.
David--
Yes the BCAL_OUT of the AO block is wired into the BCAL_IN of the PID block.
Scott--
Just double checked and the control module is assigned to the controller.
Thanks for the suggestions, guys.
You mentioned that you've done a stroke test. Can you confirm if the control valve is not in OOS mode? Please put it back to AUTO if possible.
These are the BOL article names...you should be able to see the same content in your local copy of BOL on your Deltav system if you search for these.
DeltaV fieldbus function blocks in the control strategy
Fieldbus control strategy procedures
Fieldbus PID block actual mode stuck in IMAN
In AMS, you should be able to tell what the current mode of the postioner transducer block is (without DeltaV even being linked). If it is not Auto or CAS you will likely have problems driving it from DeltaV.
In reply to Youssef.El-Bahtimy:
hmm.. I think that there is a good chance that David is correct. If you have performed a partial stroke test and have left the transducer block (or is it the resource block I can never remember) in the wrong mode it may cause the function block to stay in IMAN.
David,
The valve was in OOS mode, but when I put it In Service, it didn't change anything. We were having the problem before stroking the valve.
Youssef,
Not sure how to check the Mode in AMS... I'll look for it.
Sounds interesting. Can you please take a screenshot of what you have configured so i can look at it?
Youssef - it sounds like the OP is using conventional HART 4-20 mA. When I open HART devices in AMS I don't see any transducer "blocks" per se or modes. (Original post: "referencing the actual channel that the valve is on")
In reply to John Rezabek:
Yes, I jumped to conclusions when he stated he was using AMS and a DVC. I assumed Foundation Fieldbus.
Darrell-- I'll see if I can get a screenshot in a bit... not at the test station right now.
John/Youssef-- that's correct... it is conventional HART 4-20.