SMT - 131 Manual Ver 2.
Revision History Version 1 Version 1.1 Version 2.0 Version 2.1 Version 2.2 Version 2.3 Version 2.4 Version 2.5 Version 2.6 Version 2.7 Original Document Added Mode select in Modbus Based on version 2 Hardware (Firmware 3.0+) Added temperature calibration, DI logic and High fan limit. Added default daily start temperature (Firmware 3.03+). Corrected manual for register 40022 &40023. Added service O/ride on/off Added enhancements found in version 3.03 Firmware Added Fan Relay lock to 0-10 outputs function.
Introduction The Smart Temp SMT-131 thermostat has been designed for use in hotel rooms, guest accommodation and locations where the user will require a thermostat that is simple to use. Further, given the nature of the hospitality industry in general it is important that the thermostat be robust, flexible in function and attractive. The SMT-131 thermostat has been designed with these important goals is mind.
Note. Option 16 in the installer menu (See page 16) 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.
Take care to ensure excess wiring is not trapped between the cases half’s when closing - push excess wires into the wall cavity. Never press on the LCD when closing the SMT-131 as it may crack. Always press on the SMT-131 plastic case only.
The SMT-131 is powered by 24VAC and requires the 24VAC active and neutral to be connected to the “R” (active) and “C” (Neutral) terminals for the SMT-131 to function. The 24VAC applied to the SMT-131 “R” terminal is switch back through 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. Warranty does NOT cover this damage.
Note - When the SMT-131 calls heating or cooling the SMT-131 will drive both the relays and the 0-10V outputs simultaneously. This way the SMT-131 can call a circulating water pump via the relays as it controls room temperature with valves if needed. 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.
Maximum Value (Fan A3) output only When controlling 0-10V fans sometimes it is necessary to limit the fan speed 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 speed the 0-10V output will not exceed this pre-set high limit.
The pipe sensor needed for 2 pipe mode is the RS-1d sensor - available as an optional part from Smart Temp or an authorised distributor. Klixon Mode / 2 pipe The SMT-131 Heat and Cool mode can be changed by a remote manual mechanical switch or an automatic Klixon switch if required. ( A klixon switch is a mechanical temperature switch typically placed on a water pipe and use to detect water temperature, therefore selecting the correct thermostat mode based on the temperature of water in a fan coil).
activate the SMT-131 internal door bell. Regardless of the need to control conferential HVAC systems, 2 or 4 pipe fan coils with modulating valves the SMT-131 has the necessary outputs to achieve your control needs. Occupancy Detection The SMT-131 has sophisticated logic that when connected to your choice of movement sensors, door and window switches will automatically control the set point and mode of the SMT-131. Using part or all the functions described below are completely optional.
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 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.
activation switch with the digital input options detailed in the installer menu. (see page 17). Simply place a momentary volt free switch across “DI” and Com “0-V” terminals to activate the doorbell. Once pressed, the doorbell will chime for about 10 seconds. Outside Door Station When coupled with the optional Smart Temp door station the guest can set the room as “Do Not Disturb”, call for housekeeping or be alerted to visiting guests with a pleasant doorbell chime.
The Modbus data is provided in Addendum 1 at the back of this manual. (page 18). Modbus relies on a series connection and will normally not tolerate “Star” wiring or “T” branches. 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.
Installer Options Menu The SMT-131 has an impressive list of options that can be installer selected. These options tune the thermostat’s performance as well as set energy conservation settings. This menu is deliberately hidden and difficult to enter to discourage unauthorised tampering. The information card provided in the SMT-131 box provides details on how to enter the SMT-131 menu. If this is lost, please contact Smart Temp or an authorised distributor for support.
5 6 7 High temp set limit Low temp set limit Dead band 8 Fan Purge / Run On Period 9 Fan span 10 11 0-10V Fan Interval (PI) 0-10V Fan direction 12 14 0-10V Fan minimum value (Starting fan voltage when running) 0-10V Fan Maximum value (Maximum fan voltage when running) Heat span 15 0-10V Heat interval (PI) 16 0-10V Heat direction 17 18 0-10V Heat Voltage Cool span 19 0-10V Cool interval (PI) 20 0-10V Cool direction 21 0-10V Cool Voltage Auto Off Timer 13 22 23 24 minimum minimum U
25 Un –Occupied fan mode 26 Backlight 27 TT sensor (SI & Com) 28 Temperature Calibration 29 Digital Input 30 Digital Input Logic 31 Window Input Logic 32 Window Input Delay 33 Door Input Logic 34 Door Input Delay 35 PIR Input Delay 36 Reset Fan 37 Belimo Mode 0: Off (default) 1 – 15 minutes 1 minute steps (ver 3.
and run before heat or cool calls from the W & Y relays. 43 Thermostat response to changes in room Temperature Ver 4.04+ 44 Firmware Ver 41.1 + 2 Pipe heating threshold Firmware Ver 41.1 + 2 Pipe cooling threshold Temperature calibration Offset Ver 4.04+ 45 t r Factory Reset 0: Very Fast 1: Fast 2: Normal 3: Slow (Default) 4: Very Slow Range 5 to 50 (default 30c) Range 5 to 50 (default 20c) -9.9c to +10c 0.
Data Format Protocol Byte Format Address Baud Modbus RTU (Slave) 1 Start Bit, 8 Data Bits, 1 Stop Bit, No Parity 1 to 255 4800 / 9600 / 19200 BPS Holding Register 40001 Type Value Comments Read Only Device ID 40002 40003 Read Only Read Only Firmware Version DIP Switch State 40004 Read Write 40005 Read Only 40006 Read Write / Door Station Status 40007 Read Write / HVAC Status 40008 Read Write / Fan Status 40009 Read Write / User Set Point 40010 Read Write / Contact Reception
40011 Read /Write (Read only ver +4.
40024 Read Write / Unoccupied Fan Mode 40025 Read Write / Backlight 40026 Read Write / Remote “SI & Com 0-V Temperature Input Function 40027 Read Write / Digital Input Function 40028 Read Write Read Write Read Write Read Write / Reset Fan Mode / Belimo Mode / Modbus Address / Baud Rate 40029 40030 40031 40032 Read Only 40033 Read Only Digital Input Status 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
The 3 x 0-10V (40040 (Heat), 40041 (Cool) & 40068 (Fan)), outputs can be controlled by Modbus at any time without restriction. To permit Modbus to control the output first enter 1000 in the register you wish to override, it is then unlocked from SMT-131 control and you are then permitted to enter the value you wish the selected output to be; such as 0=relay OFF and 1 1=relay ON or 63 should you wish the 0-10v to output 6.3v. To return the output to SMT-131 control simply enter 1001 into the register.
3: Hide both mode and fan buttons Page 23
40046 Read Write / Permitted Modes 40047 Read Write Read Write Read Write Read Write Read Write Read Write Read Write Read Write Read Write Read Write Read Write Read Write / / Swap C/F display shown on display Fan Span / 0-10 Fan Interval / 0-10 Fan Direction / / 0-10 Fan Minimum Voltage.
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40066 Read Only Door Input Status 40067 Read Only PIR Status 40068 Read Only Read Write (3.09+) Read Only 0-10V Fan Value 40069 40070 0-10V Fan Max Value Digital Input logic Read Write Read Write Read Write Read Write / / Fan Relay Lock (Version 40.1+) 40074 Read Write / Temperature calibration offset (Version 40.4+) 40075 Read Write / Temperature sensor speed response. (Version 40.
Specifications Input Voltage Operating Temperature Operating RH Storage Temperature Size Display Size Backlight Display Type Relay Rating 0-10V Output Load Control Range Memory Type Communications Plastic Warranty 24VAC 50/60 Htz +/- 15% 0°C to 50°C (32°F to 122°F) 0-95% (Non-Condensing) 0°Cto 65°C (32°F to 150°F) 113 x 103 x 25mm. 69.5 x 46.3mm.
