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Remote SetPoint in PID Loop

I Need to give calculated set Point to a PID Loop. But Unable to configure. My requirement is as follows. Pl. guide

We have two Independent PID loops say Loop1 & Loop2 I want to provide Loop1 's Set Point multiplied 1.3 as a set point to Loop2. Pl. guide how to configure

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ghatevinod

• 7 Mar 2019 2:38 PM
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2 Replies

• PRASHANT-MUTTEPAWAR

  

  • 12 Mar 2019 3:48 PM

  Hi
  
  First loop is having some changable setpoint
  in the action block you can write the calculation as first pid setpoint multiplied by 1.3 factor
  after that action block output should be connected to the second pid loop setpoint .
  id the action block output is in terms of binery then you can store the acrion block calculated value to some external or internal parameter after that this parameter connect to the second pid setpoint value.
  
  Regards
  
  Prashant M

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• gamella

  

  • 13 Mar 2019 7:55 AM

  Main problem is how to feed Loop2 Setpoint having proper BKCAL wirings, manage PV scales (they may be different on Loop1 and Loop2), modes and bad/good statuses.
  Because calculated setpoint for Loop2 is a multiplication Ratio Block may be used (ratio OUTPUT = SP * IN_1 * Gain). Ratio block provides BKCAL parameters so it can be wired to Loop2 PID CAS_IN and BKCALC . (Note that Loop2 will follow Loop1 * 1.3 SP when in CAS mode).
  Choosing SP, IN_1 and Gain properly will provide desire behavior. In your case I will suggest using :
  - Loop1 SP_WRK parameter value for IN_1,
  - SP fixed to 1.3 (if a datalink is provided on a picture, operator may be able to change this factor).
  - Gain may be used to perform scale conversion between Loop1 and Loop2 PV ranges (this may require changing SP to a value different from 1.3).
  
  Will need more "context" to provide accurate answer so consider this as a particular use case.

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