User Manual

Page 11
Door Switch
The Door switch input (DS) is used by the SMT-131 for 3 functions.
1) To detect that the door has been opened and then closed to let somebody into or out
of the room.
2) To detect if the door has been left open.
3) To use as an occupancy or Auto-Off timer in training rooms or similar.
The SMT door switch input can be set for a Normally Open (switch open when door is closed) or
normally closed logic (switch closed when door is closed) or OFF (input not used). The Installer
menu 30 “Door Input Logic” and option 31“Door Input Delay” (page 17) sets the door detection
logic in the SMT-131.
Entering or exiting the room.
Once the door is opened and then closed the SMT-131 will begin its occupancy detection process
using the PIR input described below. Based on the outcome of this process the SMT-131 will
remain on and permit guest interaction with the SMT-131 (adjust mode and set point for
example), or switch to “un-occupied” mode where the SMT-131 will substitute the guest set point
and mode for the installer pre-set values.
Door Left Open
When the door is left open for longer than the pre-set time (0 to 300 seconds) the SMT-131 will
automatically turn OFF. The text “OFF” will flash in the display to indicate that the remote door
(or window switch) is holding the SMT-131 in off mode. This is done to prevent energy waste by
trying to heat or cool an open room.
The SMT-131 will automatically restart once the door is closed.
PIR input
A PIR (passive infra-red) movement detector can be directly wired to the SMT-131 “PIR” input. As
movement is detected by the PIR it will send multiple On/Off pulses to the SMT-131 every time it
detects movement. The SMT-131 using this data (with or without a door switch) will determine
the occupancy status of the room and behave accordingly. Note, the PIR must be separately
powered, typically from a 12VDC supply. Consult the PIR manual for this information. Smart Temp
do not provide a PIR sensor, and suitable alarm PIR sensor is suitable.
Latched Occupancy Detection Logic
(Typically used in Hotel applications)
Latched occupancy detection requires a door
switch and PIR input to be wired and working.
When the door is first opened the SMT-131
instantly enters “Occupied Mode” where the
SMT-131 will permit the room occupant to set
their desired temperature and mode of
operation. Once the door is closed the SMT-131
will “look” for movement as detected by the PIR
sensor wired to the PIR input. If no movement is
seen within the installer pre-set seek time
(installer adjustable 1 to 15 minutes) the SMT-
131 will return to “Un-occupied mode” where the users temperature and mode will be replaced
with installer pre-set values. Should movement be detected within the installer pre-set seek time
the SMT-131 will Latch into “Occupied Mode” and no longer rely on continued movement within