Emerson Exchange 365

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DI Charm card Loss Power

Hello, 

If I have a charm DI card that is normally closed contact (120V on the loop, and 1 for Field value in DCS module), what happens when the charm panel or CIOC loses 24V? Will the DI card open the contact, causing the Field Value in the module to be 0 input?

Thanks

DCS Newbie

• 21 May 2018 3:35 PM
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3 Replies

• Andre Dicaire

  

  • 22 May 2018 5:04 PM

  When the CHARM Panel or CIOC loses power, the DI channel will not be communicating to the controller, and the state of the Field Value D will go to:
  BAD NoCommLUV — No Communication, with last usable value (LUV). This substatus is set if this value was set by a communication that has failed.
  
  Books On Line states the Field_Value_D shows the last value reported by the input.
  The Field Value and status moves to the DI/OUT_D based on some internal logic in the DI block. The IO_OPTS has a setting called Fault State to Value- "The Output Action to take when a fault occurs. (0: freeze, 1: go to preset value).
  
  Depending on what you are trying to do, you should be able to get the desired behavior with the appropriate configuration. To be honest, I would need to do a test to confirm all these options provide what I need. The Fault State to Value looks promising.

  Andre Dicaire

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• Andre Dicaire

  

  • 22 May 2018 5:26 PM

  In reply to Andre Dicaire:

  Oops, I think I misspoke in my previous post. Thanks Matt. The IO OPTS for Fault State to Value is actually only available on the DO blocks. ( and AO).
  
  Matt checked and they are not in the DI block configuration. Sorry about that.
  
  That leaves us with the BAD NoCOMMLUV status to reflect the value is not current.

  Andre Dicaire

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• Matt Stoner

  

  • 22 May 2018 5:29 PM

  In reply to Andre Dicaire:

  So you will also have to check for bad status where you are using the value if you want something to "automatically" occur during this situation.

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