Programming Guide

VAV-SVP01A-EN 67
Sequence of Operations
Chapter Overview
This chapter contains information about the following:
• Calibration
• Occupancy Modes
• Space Temperature Control: Single Duct Units
• Space Temperature Control: Fan-Powered Units
• Ventilation Flow Control
•Flow Tracking
Normal Operation
The controller is functioning normally when it is operating in one of the three control modes (space
temperature control, ventilation control, or flow tracking control) and in one of four occupancy
modes (occupied mode, unoccupied mode, occupied standby mode, or occupied bypass mode).
Note: For More detail on control modes and units operation see CNT-SVX17*-EN.
Calibration
The calibration sequence enables the controller to calibrate the air valve position and the water
valve position. Calibration takes place if autocalibration is enabled and either a power cycle or a
transition from occupied to unoccupied has occurred.
Note: Whether or not autocalibration is enabled, the controller initiates calibration on a
communicated application mode command.
The building automation system is responsible for the staggering of the calibration sequence that
is needed between units. When autocalibration is enabled and a transition from occupied to
unoccupied occurs, the calibration sequence starts after a fixed delay of three minutes. The
controller effective occupancy mode is unoccupied, but runs like it is occupied during this three
minute period. The mode field of reported unit status reports calibration when the controller is in
the calibration sequence. If autocalibration is disabled, the air valve and water valve are not driven
closed and the flow sensor zero flow voltage reading is not recorded. Refer to Table 10, p. 67 for
calibration actions.
Table 10. Calibration actions
I/O Device Calibration Action Taken Result After Calibration
Air valve Drive the air valve closed to the stroke time plus 20 seconds
initialize the air valve position as closed when
the air valve is over-driven
Flow sensor Record the flow reading when the air valve is fully closed
Subtract the zero flow reading from all
subsequent readings
Modulating hot water reheat Drive the water valve closed for the stroke time plus 20 seconds
initialize the water valve position as closed when
the water valve is over-driven
Fan Enabled Enabled
Electric or On/Off hot water Disabled Enabled