Manual override of the damper actuator position or the desired flow setpoint on a Xenta 102-AX can be accomplished with a network variable (SNVT) input.
There are times when the damper position or flow setpoint needs to be overridden from a supervisory controller. It may be a special mode for Test & Balance, a smoke control sequence, or a special circumstance where the internal logic of the 102-AX must be ignored in some situation.
Manually controlling the Xenta 102-AX damper position, and flow value can be accomplished using the VAV_Controller.nviManOverride SNVT.
This is a three-part structured SNVT. Values for the state portion of the SNVT are:
- HVO_OFF disables override
- HVO_POSITION sets the damper position output to a desired percentage
- HVO_FLOW_VALUE sets the flow setpoint to a desired flow
- HVO_FLOW_PERCENT sets the flow setpoint to a desired percent of maximum flow
- HVO_OPEN fully opens the damper
- HVO_CLOSE fully closes the damper
- HVO_MINIMUM sets the flow setpoint to specified cooling minimum
- HVO_MAXIMUM sets the flow setpoint to specified cooling maximum
Values for percent and flow are used according to the selected state.
Click here to download a Menta macro for further clarification.
It is important to note that in versions greater than 2.1.2 no other auxiliary control will function when using nviManOverride. Example: if nviManOverride is set to control the damper to a fixed position, the external hot water heat or electric heat will not function.