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Dataset Register value (reading) mismatch in Control Studio online mode with in DeltaV Diagnostic

I have a reading of "0'" in the control studio for my dataset DS01 register R1 but the same dataset register R1 reading in DeltaV Diagnotic is showing "7". Both in same P01/DEV01.

I'm using VIM2. What could be the problem?

Rein

• 6 Jun 2018 7:47 PM
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6 Replies

• Maarten van der Waal

  

  • 7 Jun 2018 9:20 AM

  In Diagnosis, only the first element of a Dataset is shown. Right clicking on the element allows viewing the other elements.
  From your question it is not clear how the dataset is defined: element size, number of elements.
  I guess your dataset contains bits, and bit-2 and bit-3 are set, while bit-1 is zero.

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• Rein

  

  • 7 Jun 2018 7:53 PM

  In reply to Maarten van der Waal:

  Below are the Dataset properties:
  Data direction: input
  Deltav data type: Floating
  Device data type: Holding register
  Data start address: "0"
  No. of values: "10"
  Spacial Data: not used ("0")
  
  I've created a landing module for R1 to R10.
  All values in R2-R10 are matching with the values in Deltav Diagnostic except for R1.
  
  Can someone explain this bug?

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• István Orbán

  

  • 11 Jun 2018 6:41 AM

  In reply to Rein:

  Keep in mind that if you use floating point, R1 is actually R1+R2 on the slave side. Normally Modbus uses 16-bit registers, but you can map two of them to obtain floating point. I see you have 10 values in the dataset: this is 20 16-bit registers on the bus.
  I would play with the data type of the dataset: are you sure you are getting floating point, and not integers?
  Also check the parameter type in your landing module.
  You can also try the dataset's Special Data: VIM2 has options to swap the bytes.

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• Rein

  

  • 11 Jun 2018 6:50 PM

  In reply to István Orbán:

  I've made another dataset. Same as my configuration above except it's from R1 to R12 and no. of values = 6.
  
  Reading in DV Diagnostic:
  R1=0
  R2=20
  R3=0
  R4=40
  R5=0
  R6=60
  R7=0
  R8=80
  R9=0
  R10=10
  R11=0
  R12=120
  
  Reading in my landing module with external parameter as data type.
  Same as above except for R2=0.
  R1=0
  R2=0
  R3=0
  R4=40
  R5=0
  R6=60
  R7=0
  R8=80
  R9=0
  R10=10
  R11=0
  R12=120

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• Shane Moss

  

  • 11 Jun 2018 7:52 PM

  In reply to Rein:

  If memory serve me correctly, you cannot use the first 2 registers. the VIM card uses these registers for diagnostics or some other internal use. We just start our mapping with R3 and map accordingly from there. As you can see, everything from R3 down is acting correctly.

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• alex

  

  • 12 Jun 2018 3:27 PM

  In reply to Shane Moss:

  we use r1 and r2 all the time. These registers can be used.

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