Emerson Exchange 365

Controller loading with EIOC vs VIMM

Is there any reason to expect reduced controller loading when an EIOC replaces a VIM?

Since the EIOC is reported to function (in some respects) as controller, is any processing power shifted to the EIOC and could we expected reduced loading on controllers?

• EIOC
• Loading
• VIM

MPHymel

• 10 Mar 2021 9:17 PM
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6 Replies

• Andre Dicaire

  

  • 10 Mar 2021 9:45 PM

  The EIOC replaces the VIM and the control modules are moved from the controller to the EIOC.
  
  The Ethernet IO devices connected to the EIOC must be referenced by modules located in the EIOC. Once the data is landed in a control module, it can be referenced by modules running in other controllers. If the Controller to which the VIM was connected was dedicated to handling the IO from the VIM, then all those modules would be moved to the EIOC along with Ethernet IO network and devices.
  
  There are several scenarios to understand.
  1. If you were integrating motors and drives using Hardwired IO for control signals, and the Ethernet IO data was mainly diagnostic information supporting the control, you will need to leave the module where it is. You will need a new module in the EIOC to interact with the Ethernet Device and you can point the original External references to read the data from the EIOC Module. That way, all the data will still be in the original module location and will not alter the HMI references that were built on the original design.
  2. The Control Module used Ethernet IO communications for command signals and any hardwired signals were from separate shutdown modules. In that case, you can reassign the module to the EIOC. You'll have to modify the IO references to use the LDT Signal DST reference instead of the Dataset/Register number. This will offload the module from the original controller and reduce CPU loading. Any Interlock references will now be coming over the DeltaV network from the EIOC. You may want to adjust the Abort on Read error setting of expressions or take the CST (connection status) into consideration so that switchove rof the EIOC or controller does not result in spurious trips due to Status.
  3. You have a VFD working in a control loop with an AI signal connected to the controller's IO. The control loop should be moved to the EIOC (there are up to 26 PID loops available on an EIOC). The AI signal can be referenced by the AI block in the EIOC even though it remains assigned/connected to the original controller. (Outputs must be on the same node as the module writing to them). In this way, the VFD is always connected to the PID control logic and can work in MAN even if the connection to the AI host controller is lost for some reason.
  
  Remember that the EIOC is not assignable as an IO card to any controller. All the LDT references must be made from local Modules in the EIOC.
  
  In v14, the PK controller provides native integration of Ethernet devices to the controller, which in my opinion is where motors and drives should be connected to. The EIOC is primarily a sub system integration interface and is well suited for PLC integration, Analyzers, IEC61850 IEDs, and OPC UA servers/subsystems. The EIOC also has some limitations on certain types of function blocks and SFC's so be sure to know what modules you plan to move from the existing controller.

  Andre Dicaire

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• Junggyu Yu

  

  • 10 Mar 2021 10:14 PM

  In reply to Andre Dicaire:

  Hi Andre
  
  Is there a list of function block limitation for EIOC?
  
  Junggyu Yu (Remy)

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• MPHymel

  

  • 10 Mar 2021 10:16 PM

  In reply to Andre Dicaire:

  Andre,
  Thanks for the thorough reply. We are fortunate in that we perform no writes over our VIMS, and only have AI and DI indication from the systems that will make use of our EIOCs, so I do not expect to run into the issues you described.
  
  It is good to be aware of this however.
  
  We EE365 users really appreciate the amount of effort you key contributors apply to this site. I can't thank you enough.

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• Piero Ranieri

  

  • 21 Apr 2021 1:58 PM

  In reply to Andre Dicaire:

  Hi to everybody, I'm a newbie inside this forum, and I would like to have your support in relation to VIM Card and EIOC Card.

  I have an existing Delta V system with a lot of VIM card, it will be foreseen a system expansion with external TCP/IP equipment to be managed too. Emerson offer EIOC Card with DV system, instead VIM Card.

  Customer is requiring to collect the expansion and existing into a central control room as per architecture (see picture attached).

  Question: Could EIOC and VIM Card co-existing on the same network ? As I read the configuration Machine shall not be more used with EIOC it's correct ? Shall I insert some additional hardware and/or software for co-existing VIM and EIOC ?

  Thank you

  

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• Andre Dicaire

  

  • 21 Apr 2021 3:29 PM

  In reply to Piero Ranieri:

  Pierro, You should "create new post" so your topic can be discussed in context of your question.

  Andre Dicaire

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• Wes Urbat

  

  • 10 Jul 2024 9:27 PM

  In reply to Andre Dicaire:

  Andre,
  
  Thank you for this post. The detailed best practices helped our site recognize a failure scenario we missed in our initial implementation and has enlightened us to other alternative hardware configurations for interfacing to VFDs.
  
  Wes

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