Smart Temp SMT - 131 Manual - page 12
Page 12
Data Format
Protocol
Modbus RTU
Byte Format
1 Start Bit, 8 Data Bits, 1 Stop Bit, No Parity
Address
1 to 255
Baud
4800 / 9600 / 19200 BPS
Holding
Register
Type
Value
Comments
4000
1
Read Only
Device ID
Always Returns “131”
Use As A Sentinel Point
4000
2
Read Only
Firmware Version
Divide By 100 (e.g. Version 2.36 = 236)
4000
3
Read Only
DIP Switch
Settings
Binary Count
Sw 1 = 1, Sw2 = 2, Sw3 = 4, Sw 4 = 8 etc
4000
4
Read / Write
Occupancy Status
0 = Room is Unoccupied
1 = Room is Occupied
Note - Modbus can write “0” holding the
room unoccupied regardless of the occupancy
input.
Modbus cannot override the occupancy input
and hold the SMT-131 in occupied mode.
4000
5
Read Only
Bell Status
0 = Bell Is Silent
1 = Bell Is Chiming
4000
6
Read / Write
Door Station
Status
0 = Normal - No Activity
1 = “Make Up Room” Active
2 = “Do Not Disturb” Active
4000
7
Read / Write
HVAC Status
0 = Air Conditioning Off (1 or 3 Fan Speed)
1 = Low Speed Ventilation ( 1 or 3 Fan Speed)
2 = Med Speed Ventilation (3 Fan Speed Only)
3 = High Speed Ventilation (3 Fan Speed only)
4 = Air Conditioning ON (1 or 3 Fan Speed)
4000
8
Read / Write
Fan Status
3 Fan Speed Mode
0 = Low (Fan Auto)
1 = Med ( Fan Auto)
2= High (Fan Auto)
3 = Auto Fan Speed (Fan Auto)
4 = Low (Fan On)
5 = Med (Fan On)
6 = High (Fan On)
7 = Auto Fan Speed (Fan On)
1 Fan Speed Mode
0 = Fan Auto
4 = Fan On