LX Series Unit Ventilator Controller User's Guide
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Note:
Any commands by nviOccCmd can be overridden by nviOccManCmd as
shown in Table 5. For nviOccCmd to be effective, nviOccManCmd must
be set to OC_NUL.
Ending Standby Mode
The Unit Ventilator Controller exits from standby mode when any of the following
occurs:
•
The bypass button on the temperature sensor is pressed or the bypass contact
input is ON. These events initiate bypass mode.
•
The occupancy contact is closed. This initiates occupied mode.
•
The network variable nviOccManCmd is set to another value by an operator or
program.
•
The network variable nviOccManCmd is set to another value while
nviOccManCmd is set to OC_NUL. This method can be used to follow a
schedule.
•
The window contact is closed; the occupancy status sets to
OC_UNOCCUPIED.
Slave Mode
The Unit Ventilator Controller enters slave mode when nviSlave
(SNVT_hvac_status) is bound to the nvoUnitStatus of another ventilator. The
UVC attempts to follow the heating or cooling demand of the other unit.
State Selection and Description
The Unit Ventilator Controller enters occupied, unoccupied, standby, and bypass
modes depending on the schedule, and other inputs such as the bypass contact
switch. Within each mode, the UVC can enter various states such as heating,
cooling, night purge, and morning warm-up.
Supervisory Control and Scheduling
The network variable nviApplicMode coordinates the Unit Ventilator Controller
with a supervisory control such as a schedule or a Human-Machine Interface
(HMI). The variable nviApplicMode is a SNVT_hvac_mode and must be bound to
a network variable output that is also a SNVT_hvac_mode from the HMI,
supervisory control, or air handler.
When this connection is complete, the HMI or supervisory control sets the Unit
Ventilator Controller to different states through nviApplicMode.
