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DVC6200 Feedback problem

Hi all,

We have a strange problem with a lot of DVC6200 positioner , I'm using Siemens Hart DO modules to sent 4-20 mA to valves and get the feedback through Hart communication, what is very strange "when I sent command in range from [2%-100%] the feedback is fine and the valve correspond fine, but when I sent 1% or 0% the valve correspond also fine but the feedback is -22%, I don't know where is the missing

please help.

• DVC6200 SIS

amrnassef

• 4 Dec 2015 6:47 AM
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3 Replies

• MOH

  

  • 4 Dec 2015 9:14 AM

  Hi
  Yokogawa DCS has option ( shut close, or simthing like that) when the value is less than pre configure value, DCS send value less than 2 ma ( valve be closed by failure). check the PLC may has same option

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• amrnassef

  

  • 4 Dec 2015 10:10 AM

  In reply to MOH:

  thanks for reply, but i measured the current reached to valve when i sent 0% command and it was 3.9 ma and still FB is -22%

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• John Brinson

  

  • 4 Dec 2015 1:12 PM

  Are you sure your HART variable is actual valve position and not the positioner internal setpoint? Lo Limit/Cutoff Select default is "Cutoff", and the positioner internal setpoint will go to -23% with an analog input of 0.5% (4.08 mA) or less to ensure travel saturation. (page 19 of November 2014 manual) The same thing applies to the upper analog input as well. I know this is not exactly the scenario you are seeing, but it may help. Good luck.

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