Summary of SMT - 131
Page 1
Smt - 131 manual ver 2.1.
Page 2: Index
Page 2 revision history version 1 original document version 1.1 added mode select in modbus version 2.0 based on version 2 hardware (firmware 3.0+) version 2.1 added temperature calibration, di logic and high fan limit. Index index 2 introduction 3 thermostat operation 3 installation - hvac control ...
Page 3: Introduction
Page 3 introduction the smart temp smt-131 thermostat has been designed for use in hotel rooms and other locations where the user will require a thermostat that is simple to understand and functions in a logical manner. Further, given the nature of the hospitality industry in general it is important...
Page 4
Page 4 note. Option 16 in the installer menu (see page 15) permits you to set the smt-131 to automatically reset the indoor fan to automatic mode (cycle on and off with heating and cooling) every time the thermostat is turned off and then back on if desired. Ventilation mode if permitted by dip sw7,...
Page 5
Page 5 dip switch settings switch function on off sw1 indoor fan mode 3 fan speed 1 fan speed sw2 equipment type heat pump heat cool sw3 hp mode (sw2= on) hc mode (sw2=off) rev valve heat (b) he – fan with heat rev valve cool (o) hg – no fan in heat sw4 2 / 4 pipe mode 2 pipe mode 4 pipe mode sw5 co...
Page 6
Page 6 the 2a relays to the equipment. Note the drawing provided here. Caution - although the smt-131 is a robust device, wiring errors can potentially damage the thermostat. This damage is not covered by warranty. Take care when wiring 24v near sensor inputs or the modbus communications terminals. ...
Page 7
Page 7 0-10v outputs to permit the control of modulating heating and cooling valves as well as variable speed dc fan motors or variable capacity hvac systems the smt-131 has been fitted with 3 x 0-10v outputs. The 0-10v outputs in the smt-131 are pi (proportional integral) controlled. This control m...
Page 8
Page 8 maximum value (fan a3) output only when controlling 0-10v fans sometimes it is necessary to limit the fan spped to reduce noise or to protect ducting. The fan output has a high voltage limit setting so regardless of the user selected speed (high, medium or low) or thermostat selected auto spe...
Page 9: Ancillary Functions
Page 9 ancillary functions the smt-131 has a number of additional capabilities such as communications with building automation systems via its modbus communications port. The smt-131 will automatically control temperature set points based on occupancy of the room when a suitable door switch and move...
Page 10
Page 10 window contact the window contact input (wc) is used to automatically disable the hvac system if a window is left open. This is done to prevent energy waste by trying to heat or cool an open room. The smt-131 window input can be set for a normally open (switch open when window is closed) or ...
Page 11
Page 11 automatic occupancy detection logic automatic occupancy detection requires the 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 guest to set their desired temperature and mode of o...
Page 12
Page 12 or guest’s needs by text information displayed on the door station lcd or the door station backlight colours. Connection between the smt-131 and the hotel door station is cable fitted with rj12 plugs. Cables can be provided at additional cost at up to 15 metres maximum. Alternatively custom ...
Page 13: Installer Options Menu
Page 13 remote temperature sensors occasionally the room thermostat cannot be installed in the ideal location to measure the room temperature accurately. In these circumstances the smt-131 can use optional remote temperature sensors. These are a two wire device, not polarity dependent and simply wir...
Page 14
Page 14 option list table option setting 0 buttons shown 0: both mode and fan buttons show (default) 1: show mode but fan button hidden 2: show fan but mode button hidden 3: both mode and fan buttons hidden 1 permitted modes 0: off / auto 1: off / auto / heat / cool 2: off / heat /cool 3: off / heat...
Page 15
Page 15 17 0-10v heat minimum voltage 0 -10v data format : 0-10v heat minimum value * 10 18 cool span 0.5c-3.0c/1.0f-6.0f 0.5c/1f steps data format : fan span * 10 19 0-10v cool interval (pi) 10-300 seconds 10 seconds steps (60 seconds default) 20 0-10v cool direction 0: 10v is 100% open (forward ac...
Page 16
Page 16 39 baud rate 1: 4800bps 2: 9600bps 3:19200bps 40 factory reset 0: no 1:yes (exit to initiate) modbus data – addendum 1 the smt-131 has integrated modbus rtu communications. Using a modbus master controller such as the smart temp 770-hmi many of the smt-131 thermostat features can be centrall...
Page 17
Page 17 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 ...
Page 18
Page 18 400 18 read / write fan purge period 0 = off 1 = fan purge - 1 min 2 = fan purge - 3 min 3 = fan purge - 5 min 4 = fan purge - 10 min 5 = heat only fan purge - 1 min 6 = heat only fan purge - 3 min 7 = heat only fan purge - 5 min 8 = heat only fan purge - 10 min 9 = cool only fan purge - 1 m...
Page 19
Page 19 400 24 read / write unoccupied fan mode 3 fan speed mode 1 = low (fan auto) 2 = med ( fan auto) 3 = high (fan auto) 4 = low (fan on) 5 = med (fan on) 6 = high (fan on) 1 fan speed mode 0 = fan auto 4 = fan on 400 25 read / write backlight 0 = on with button press 1 = always on (high) 2 = alw...
Page 20
Page 20 values below only apply to version 2 hardware only, firmware version 3+ 400 43 read / write 2 pipe mode changeover 0 = heat 1 = cool 400 44 read / write thermostat displaying 0 = deg c 1 = deg f 400 45 read / write buttons shown on display 0: both mode and fan buttons show (default) 1: show ...
Page 21: Specifications
Page 21 400 67 read only pir status 0:no movement detected 1:movement detected 400 68 read only 0-10v fan value value / 100 (e.G. 2.1v = 210) 400 69 read only 0-10v fan max value 0-10v (@*10) 400 70 read / write digital input logic 0:normally open 1:normally closed specifications input voltage 24vac...