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What SNVT_temp_p value in the AS local node is required to force an MNL controller to fallback to a Not Active (NA) condition?

Issue

What SNVT_temp_p value in the AS local node is required to force an MNL controller to fallback to a Not Active (NA) condition?  The AS station is configured to use degrees Fahrenheit and standard SNVT_temp_p definition uses degrees Celsius.

Environment

StruxureWare Building Operation

Cause

SNVT_temp_p is defined by the standard as a degrees Celsius temperature with a range of - 273.17 to + 327.66 Deg C (0.01 Deg C).  A value of 327.67 Deg C (0x7FFF) will cause the MNL controller to fallback to an NA condition.  The AS station is configured to use degrees Fahrenheit the value must be entered in Deg F.

Resolution

Sending a Not Active (NA)

To write SNVT values, one is to write from programming logic to the local node out of the mirrored network variable to the controller SNVT.  Example: Mirrored variable, local node -> Vav??? -> nvoSetpoint, writes to VAV??? nviSetpoint [MNL-V2RV3]

  1. Go to the local node
  2. Find the nvoSetpoint
  3. Expand to Temperature value
  4. Right-click and select Properties
  5. Under Basic tab, General Information Section, Limit Section, locate the Invalid value
  6. Use the following value for NA in your programming [for SNVT_temp_p it is 621.81]
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Revision #:
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Last update:
‎2018-09-06 09:50 AM
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