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connecting a parameter from on control module class instance to another control module class instance within an equipment module Class

Good Morning,

I am creating a equipment module class to control 5 sets of equipment that are identical in devices and logic.

I have created the Eq Mod class and within it have placed two control module class instances.

In short the Eq Mod controls a flow control valve based on a flow meter reading, using a PID loop.

One control module class is for the flow meter, and consists of an AI block.

The other is the PID block that controls the valve.

I would like to connect, within the Eq Mod class, the output of the flow meters AI block to the input of the PID, so that in any instance of the Eq mod I only have to connect the flow meters DST to the flow meter control module class instance and the flow valve to the PID control module class instance, using the configure IO program.

I want the PID block input within the PID control module always look at the flow meter AI block output inside the Flow meter control module within the same Eq module instance.

I have worked around this by adding an AI block in the PID control module class, but the problem is when I configure IO for the Eq Mod instance I have to connect the flow meter DST to both the flow meter control module and the PID control module of that Eq Mod class instance.  This prompts a warning and I would rather not keep it this way.

I have tried using an input parameter in the PID control Mod, and setting it to external reference (leaving the path blank) hoping it would show up in the Configure IO screen but it does not, and causes a warning when trying to download.

Any help on this would be greatly appreciated.

Tyson

• Equipment Module Class Control Module Class Configure IO

TysonK

• 23 Apr 2016 1:00 PM
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8 Replies

• Maarten van der Waal

  

  • 23 Apr 2016 1:09 PM

   would advise to use your 'work-around' as the full solution. Then you don't need the AI module anymore, and you only have to connect you DST just one time.

   

  Good luck, Maarten.

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• TysonK

  

  • 23 Apr 2016 1:17 PM

  In reply to Maarten van der Waal:

  Thank you for your reply.
  
  I had considered it, although further down the road there will be another control module added to the Eq Mod that will also be looking at the flow meter input and at that time I will be faced with the same scenario.
  
  There must be a way to connect parameters between two (or more) control modules within an Equipment Module.
  
  Regards,
  Tyson

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• TysonK

  

  • 25 Apr 2016 11:51 AM

  In reply to TysonK:

  Does anyone know a solution to this question?
  
  Is more Info required?

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• Maarten van der Waal

  

  • 25 Apr 2016 4:17 PM

  In reply to TysonK:

  When you show a parameter with the process-value (internal reference within the AI-class) from your AI-class in the EM, you can link this value to a parameter in the PID-class. The latter parameter has to be connected to the IN parameter of the PID function block. Other information from the AI-class can be used the same way.

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• TysonK

  

  • 25 Apr 2016 4:41 PM

  In reply to Maarten van der Waal:

  Thanks for the reply,
  
  Just so I am clear; In my AI control module class, AI block I select show parameter - PV
  I then create an input parameter in my PID control module class (lets call it Flow_In), and connect it to the input of the PID block.
  -both of these control module classes are used in a common equipment module class.
  
  Then in the Equipment module class instance, I select Flow_In, in the PID control Module instance and uncheck 'Use default value from library object', and then connect it the AI control module instance AI1/PV?
  
  Is this correct? Is it possible to do the connect within the equipment module class?

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• Maarten van der Waal

  

  • 25 Apr 2016 5:23 PM

  In reply to TysonK:

  The way I have set it up as a test is to show the parameter PV from the AI-(class)module, and link it inside the EM-class to the 'FLOW_IN' parameter in the PID-(class)module.
  The 'FLOW_IN' parameter inside the PID class is a float-with-status.

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• TysonK

  

  • 25 Apr 2016 5:52 PM

  In reply to Maarten van der Waal:

  Thank you,
  
  I was able to create a new EM and duplicate what you describe. The test EM I made was a standard function block, so when opened in Studio it shows blocks representing the FlowAI(CM class) and the FlowCtrlPID(CM class). I then used a line to connect the AI PV to the Flow_in parameter of the PID. Is this how you made this work?
  
  Unfortunately, my original EM is a Command Driven Module and does not allow me to connect (link) from a block representing the FlowAI to the FlowCtrlPID.
  
  Any suggestions?

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• TysonK

  

  • 25 Apr 2016 5:57 PM

  In reply to TysonK:

  Ah, got it!
  
  In my original Command Driven EQ module I switch the view to Function block and was able to duplicate the above procedure .
  
  Thanks a Bunch,
  Tyson

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