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]
- Go to the local node
- Find the nvoSetpoint
- Expand to Temperature value
- Right-click and select Properties
- Under Basic tab, General Information Section, Limit Section, locate the Invalid value
- Use the following value for NA in your programming [for SNVT_temp_p it is 621.81]
