User Manual

Sequence of Operation
Occupancy Notification
19
Siemens Industry, Inc.
Application Note, App 14900
140-1231
2020-02-11
Figure 4: Humidification and Dehumidification Operation.
HmdySp: Humidification Setpoint, user-adjustable to desired level in Humidification
mode.
DeHmdySp: Dehumidification Setpoint, user-adjustable to desired level in
Dehumidification mode.
HUSP DB: A deadband maintained between the HmdySp and the DeHmdySp. If one
changes, the other dynamically shifts to maintain at least a 15% gap.
HU DB: Humidification/Dehumidification Deadband.
Occupancy Notification
Many internal control sequences rely on occupancy status, for example: room setpoint
choice, fan operation, and economizer enable. Occupancy Notification also goes out
from a configurable relay to enable external equipment. The space is assumed to be
occupied when the schedule mode is set to Comfort. An optional occupancy sensor
can also be used for definitive proof of occupancy (manual override to the room
temperature setpoint is the evidence that the space is being occupied).
The thermostat uses three methods to determine if the space is occupied: scheduler,
manual override, or occupancy sensor.
● To use the Occupancy functions, the thermostat must have an active schedule.
The local scheduler does not have the direct information about occupancy; instead,
the space is assumed to be occupied when the schedule mode is set to Comfort.
● During periods in which the schedule indicates the space is unoccupied, any
human interaction with the thermostat (for example, setpoint adjustment) will put
the thermostat into Occupied mode.