User Manual

Page 12

the room to remain in “Occupied Mode”. This ensures that the room remains a conditioned space

even if the occupant stops moving or sleeps for example. Next time the door is opened and then

closed again the SMT-131 will again begin its occupancy detection process.

Note - even when the SMT-131 is in “un-occupied mode” it will continue to use the PIR input to

determine room occupancy. For example – in a hotel a couple may be staying in the room and

one leaves the room leaving the other asleep in bed. As the door closes the SMT-131 will seek

movement and when none is found it will enter “un-occupied mode". As the sleeper wakes and

then moves the SMT-131 will automatically re-enter “Occupied Mode” even though it may have

been some time since the door was closed.

Installer option “PIR Input Delay” (page 17 ) sets the PIR mode (On or Off) and the seek time value

(1 to 15 minutes).

Using a PIR Only for occupancy Detection

(Typically used in meeting or class room applications)

When you require the SMT-131 to turn the Heating and

Cooling on when people enter a room and off when

people exit the room such as maybe the case in a

conference or class room.

Wire the PIR directly to the DS (door switch input) of the

SMT-131. When movement is detected by the PIR sensor

the SMT-131 will turn the Air conditioning on maintain

the set point. After the last person has left the room the

SMT-131 will wait an installer defined time and then

switch to "Un-Occupied Mode"

Steps to use the SMT-131 in automatic occupancy detection mode.

1. Wire the PIR movement detector into the DS (Door Switch) input.

2. Set the PIR input delay period (See page 17 for information on setting the

PIR input delay) to the number of minutes that you wish the Airconditioning

to run after the last movement has detected in the space.

3. Place a link permanently shorting the PIR input to Com 0V.

Manual Occupancy Input

The DI (Digital Input) & Com 0-10 terminals within the SMT-131 can be used to instantly force the

SMT-131 into “Un-occupied Mode”. This input can be wired to a simple card reader or other 3

party system that may be pre-installed for room occupancy detection.

When the SMT-131 is in “Un-occupied Mode” the display will go completely blank except for the

words “Unoccupied” in the top left corner. If the optional HOT-243 hall way panel is installed its

display backlight will go out to let housekeeping know the room is empty. Modbus register 40004

also indicates occupancy status.

Doorbell

A built-in doorbell feature is included with the

SMT-131 thermostat. This is normally activated by

the optional outside door station as described

above or via Modbus data link. In circumstances

where this is not convenient the Digital Input (DI)

terminals can be reassigned as a doorbell