Emerson Exchange 365

Communication Errors From Krohne Flow Meters Causing Spurious Flow PVs

Folks, please share any of your previous encouters on this issue:

System: DeltaV 11.3.1

AMS: 11.1.000.085

We have two Flow Transmitters from Khrone (M10 and M20) connected to a 8 channel, Series 2, HART redundant AI card.

Channel 4: Krohne ESK4 M40 Rev 1 Variable Area Flow Meter

Channel 5: Khrone M10 Rev 2  Variable Area Flow Meter

These two transmitters generate a pattern of events that propogate to the A&Es in DeltaV and AMS Audit Trail. Below are the sequence of status alerts seen in Audit Trail and there are intermittent.

* ABNORM: Extended Module ESK4-IO Detected

*ADVISE: Configuration Change

*COMM: Communications failure

Everytime a communication failure triggers a negative field value from the flow transmitter and the flow drops suddenly to a negative valve just below zero and recovers to a steady flow value after 6 seconds approximately as seen on the flow trends.

When I disable HART functianlity on these chennels and monitor the flow, the spurious flow PVs diappear.

• Khrone
• HART

FireFly

• 1 Feb 2016 6:32 PM
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3 Replies

• Arturo Medina

  

  • 1 Feb 2016 7:27 PM

  Hello.
  First, the errors are being generated by the field devices. AMS and DeltaV are just displaying them. If you absolutely want to get to the source of the problem, you will have to re-check the field devices configuration and status.
  Of course the errors will go away if he turns the channel into regular Analog! But that will also disable all of the AMS and HART functionality on DeltaV and AMS.
  If , however, you want to continue to use AMS and the HART functionality, but avoid a HART error from causing your PV go to BAD status, I would start by reviewing how you have the Control Modules configured, make sure you mapped Field Val Pct.
  I am almost sure, however, that you mapped the HART FIELD VAL into the AI block, therefore you will have to go into the HART ERRORS for that channel and mask out the errors that are making the PV BAD, (I am interpreting this as the COMM Failure seen in DeltaV).
  Let me know if you don't know how to do this and I will be happy to guide you.: Arturo.medina@emerson.com

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• Jonas Berge

  

  • 2 Feb 2016 2:15 AM

  The communication error could be due to some installation issue. Make sure the installation meets HART requirements if you use HART communication in continuous mode. Digital HART communication is more demanding than analog 4-20 mA with respect to cable type, shield, grounding, capacitance (may have to be polyolefin insulation), length, and separation from power cables etc. Make sure to follow the recommendations found here:
  en.hartcomm.org/.../usinghart_wirelength.html
  
  If there is noise on the wire the secondary, tertiary, and quarternary variables will stop coming. You will not get the updates. You may not notice such issues when you just use a handheld for device configuration and commissioning, but once you do continuous monitoring it will be evident. Just make sure to install it right and you will be OK.
  
  Field communications troubleshooting tips:
  www.eddl.org/.../ag_Field Communication Troubleshooting.pdf

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• FireFly

  

  • 2 Feb 2016 10:02 PM

  In reply to Arturo Medina:

  Hi Arturo, I checked the logic in Control Studio, we have used Field Val Pct only.

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