Emerson Exchange 365

• Not Answered

Analog Output Modes

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

depthcharge623

• 1 Jul 2014 6:58 PM
• Cancel

20 Replies

• Otto Von Steele

  

  • 3 Jul 2014 12:55 AM

  In reply to depthcharge623:

  The DCV's are pretty fishy when it comes to HART and what you put in the XD_SCALE as far scale and units, and so on when you have HART enabled on the channel.

  1. Dumb down the channel to just be a regular 4-20mA (not HART) and configure the AO block with XD_SCALE/PV_SCALE to 0-100 %.  If it works, then it lets you know it's more of the HART component and the units you chose.
  2. Enable HART back on the channel and set the XD_SCALE to 0-100 but leave the units blank while having PV_SCALE 0 - 100 %.  Normally on a download, it'll automatically tell you which units need to be there and you can upload it into the module.
  3. Don't tie IO_READBACK directly into the AO block.  I'd first configure an AI block if you're using readback and see what the value is.  Depending on the DVC model and firmware, it gives pretty awesomely random numbers (i.e. it'll scale the readback from 275 to 375 where 375 is the 0%, etc).

  Hope that helps.  You're not alone having issues with DVC's with HART enabled on the channel.

  • Cancel
• Tinh Phan

  

  • 3 Jul 2014 7:14 PM

  In reply to Otto Von Steele:

  I do agreed with Otto Von Steele.  If you are using HART, you will need to make sure that the unit and scale of the XD_SCALE matches what in the device.  Otto mentioned in his step two to upload and download the module to sync the unit and scale from device to the DeltaV module.  Note:  when you change the AO block XD_SCALE to "no unit", you will need to save and download then do another download before the controller will request the new unit/scale from the device to upload.

  • Cancel
• James Suisse

  

  • 10 Jul 2014 9:53 PM

  In reply to depthcharge623:

  I'm not sure if this is related or not, but I have had a similar problem configuring DVC6000 and 6200's.  With HART enabled, the AO block would go into error in DeltaV.  We eventually found the problem was the technician that originally configured the DVC set its Analog Input range to 4-20mA instead of 0-100%.

  To solve this, I opened the DVC in AMS Device Manager, and made sure the Detailed Setup>Instrument>Analog Input Range was changed from 4-20mA to 0-100%.  As soon as I put the DVC back in service, the error went away.

  James Suisse

  • Cancel
• Aaron Crews

  

  • 11 Jul 2014 10:04 PM

  In reply to depthcharge623:

  "I have a DVC6200 Fischer control valve connected to the system via analog input (M-series input card and controller) "

  Just so that I am not assuming anything... can I assume that you mean that it is wired to an Analog *output* card?

  When I have had these issues in the past, it has always been the mode of the transducer block in the DVC.

  • Cancel
• depthcharge623

  

  • 14 Jul 2014 1:49 PM

  In reply to Aaron Crews:

  Thanks for the suggestions guys... hope to try a few of the HART related ones today, so I'll let you know.

  Aaron, sorry for the miscommunication-- the valve is wired into an Analog Output card.  

  • Cancel