Emerson Exchange 365

Maximum and minimum value of a single parameter

Sir,

How to find the minimum and maximum value of a single parameter. Eg I need to find the min and max speed of machine for 8hrs. Thanks in advance

royalvnm

• 28 Mar 2021 6:10 AM
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4 Replies

• vmvmhatre

  

  • 28 Mar 2021 9:20 AM

  Can you clarify requirement more:
  
  Required minimum and maximum of a process variable in current shift (shift of 8 hours separated by time of day) ?
  or
  Required minimum and maximum of a process variable in 8 hours time slot back to current time ?

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• royalvnm

  

  • 29 Mar 2021 2:15 PM

  In reply to vmvmhatre:

  yes maximum and minimum value of single parameter every shift.

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• vmvmhatre

  

  • 29 Mar 2021 4:27 PM

  In reply to royalvnm:

  DTE block can be used to generate timed pulse at start of shift.

  Refer approximate code that can be put in action block that will calculate maximum and minimum value of input parameter.

  In addition, array parameters can be used to store maximum and minimum of previous shifts.

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• Andre Dicaire

  

  • 29 Mar 2021 4:43 PM

  In reply to vmvmhatre:

  The DeltaV Continuous Historian provides Min Max values for specified time periods. A shift End Report from DeltaV Reporter can include Min Max values for all historized values, without adding Module code. The min max values are also available in the PHV history Trends.
  
  VMVMHATRE gives you a starting point to create this in your control module. You will need to add a couple of parameters to capture the values at end of shift and show them as "LastMax, LastMin" before you reset the Current Min/Max values at shift change. you could also build a separate module to monitor various values for Min Max and provide the results to a display for shift change. This would allow you to manage this data without downloading your running modules. you could also place this monitoring module in an App station rather than the controller, especially if you want to do many of them and controllers are already loaded.
  
  The Reporter can also give you averages and accumulations based on the history data. If you are using the Advanced Historian or Legacy Historian based on PI, the PIDatalink Addon for Excel can be used to retrieve this information as well.

  Andre Dicaire

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