Emerson Exchange 365

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Hidden Namesets

There is a hidden nameset in DV called $BYPASS that SUPERUSER cannot find/view.

How can I view these hidden nameset and its values?

• DeltaV #DCS
• PID

Eddie Villarreal

• 1 Jun 2020 1:35 PM
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13 Replies

• SBPosey

  

  • 1 Jun 2020 1:53 PM

  $bypass (lowercase -- named sets are case sensitive) has 2 entries: Off (1) and On (2). Both entries are visible and user selectable. This named set is used by the signal characterizer block (SGCR). Looking through a full-export .FHX file for our system, I don't find an uppercase $BYPASS named set. Is that a named set that your facility created? I am not aware of a mechanism to hide named sets.

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• Mark Bendele

  

  • 1 Jun 2020 2:03 PM

  In reply to SBPosey:

  It's used in the PID block too.

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• SBPosey

  

  • 1 Jun 2020 2:43 PM

  In reply to Mark Bendele:

  The complete list is: PID (normal [PID], conditional alarming [PIDWCALARM], foundation fieldbus [FFPID], foundation fieldbus Rosemount extended [FFPID_RMT]), Fuzzy Logic Controller (normal [FLC], conditional alarming [FLCWCALARM]), Signal Characterizer [SGCR].

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• Eddie Villarreal

  

  • 4 Jun 2020 1:14 PM

  Thanks for the replies.

  I wanted to add that I used the following IF condition to calculate parameters with the assumption the value OFF was equal zero and not 1.

  IF '/PID1/BYPASS.CV'  then …. 

  When the condition did not work, I tried to search for the $bypass nameset to verify its named value but could not find it.

  

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• Matt Stoner

  

  • 4 Jun 2020 1:23 PM

  In reply to Eddie Villarreal:

  As SBPosey posted the values are Off (1) and On (2) which will always be True in your IF expression shown. Add "= 1" for Off or "= 2" for On to your IF condition check.

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• Mark Bendele

  

  • 4 Jun 2020 1:36 PM

  In reply to Matt Stoner:

  I have done this by " = '$bypass:Off' " and " = '$bypass:On' "

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• Eddie Villarreal

  

  • 5 Jun 2020 1:22 PM

  Thanks for confirming the $bypass values. I found the values of the $bypass nameset using WATCHIT but going back to my original post, is this $bypass named set locatable to view its contents in library? I could not find it via search tool. I ask this should there be other hidden named sets we encounter. Are these hidden named sets visible in library or are its content values listed in HELP? Sorry for the confusion.

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• vmvmhatre

  

  • 5 Jun 2020 1:56 PM

  In reply to Eddie Villarreal:

  These Named sets associated with DeltaV functions blocks can not be located in DeltaV explorer.
  
  Also they are not browsable when assigning to custom parameter in configuration. But can be assigned with some alternate non-routine configuration method.
  
  Also these Named sets are not browsable when to be used in expression. but when typed, it parse successfully.

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• Mark Bendele

  

  • 5 Jun 2020 4:05 PM

  In reply to vmvmhatre:

  It is true that you can't browse for them and you can't view them under setup/named sets in DeltaV Explorer.  But you can see them by viewing the properties of the parameter.  You can see the visible names in the named set by clicking on the drop down.  You don't see the value associated with each visible name, but you don't need that to do comparisons.  You can use the named set names, such as '$bypass:Off'.

  

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• Andre Dicaire

  

  • 5 Jun 2020 4:39 PM

  In reply to Mark Bendele:

  So why does Emerson hide these Named Sets? It might be best to not use these internal Named Sets in user code. It's more of a future support thing. If the $bypass Named Set is modified in the future (or any of the hidden $NamedSets), Emerson will not be aware of said use, and expects they can change these without consequence to user code.
  
  I'd say the odds are low the $bypass would change, and likely if it did, the current values for 1 and 2 would likely remain, but maybe its better to create your own Named Sets for user configuration and leave the hidden ones, well, hidden.
  
  "Just because you can, doesn't mean you should..."

  Andre Dicaire

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• Eddie Villarreal

  

  • 5 Jun 2020 4:58 PM

  In reply to Mark Bendele:

  The named set names can be viewed in properties but the values associated with those names cannot so there was confusion when trying to use as a Boolean. It was assumed the $bypass named set values were standard (OFF=0, ON=1).

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• Dmitrii Kapitonov

  

  • 6 Jun 2020 8:40 AM

  In reply to Eddie Villarreal:

  There is one of ways to get value of namedset. You can use integer parametr type.

  

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• SBPosey

  

  • 8 Jun 2020 11:55 AM

  In reply to Eddie Villarreal:

  In a standard export .FHX file, a named set is called an "ENUMERATION_SET". $bypass is defined in something called a "SYSTEM_ENUMERATION_SET", which is the same type of thing which defines option bitstrings. Both named sets and option bitstrings are structured the same way: they both associate a text string with a numeric value. How they are used is different: Named sets associates a string with an equivalent value ('$dc_fail:Tripped' and 7 can be used interchangeably in a controller). Option bitstrings, on the other hand, associate a text string with a bit number (0-15) and are typically used where you can select multiple entries, such as options (hence the name). '$control_opts:Direct Acting' has value of 10. If "Direct Acting" is the only option selected for a PID block, CONTROL_OPTS will have a value of 1024 (2^10). I do not know why most named sets are of type "ENUMERATION_SET", but some are "SYSTEM_ENUMERATION_SET".

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