SyxthSense SRC-131 User manual

SRC-131 Modbus Hotel Room
Controller User Manual
SyxthSense Ltd. 3 Topsham Units. Dart Business Park.
Topsham. Exeter. Devon. EX3 0QH. United Kingdom.
Tel: [phone] Fax: [phone]
www.syxthsense.com

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Copyright Notice
This document has been prepared by SyxthSense Limited using (i) its own proprietary information and (ii)
proprietary information owned and controlled by other third parties (for which SyxthSense Limited has a right to
use). The contents are copyrighted and must not be communicated in whole or in part to any other party without
the prior written approval of SyxthSense Limited.
The following notice applies to this document and shall be reproduced on any permitted copies:
© 2016 SyxthSense Limited. All rights reserved.
Any request for further information concerning this document should be addressed to:
SyxthSense Limited
3 Topsham Units
Dart Business Park
Topsham Exeter
EX3 0QH
United Kingdom

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CONTENTS
1INTRODUCTION................................................................................................................... 4
2CONTROLLER OPERATION.............................................................................................. 4
3INSTALLATION .................................................................................................................... 5
3.1 SYSTEM DESIGN.................................................................................................................. 5
3.2 OPENING WALL CONTROLLER ............................................................................................ 5
3.3 MOUNTING WALL CONTROLLER......................................................................................... 5
3.4 DIP SWITCH SETTINGS........................................................................................................ 5
3.5 WIRING –HVAC CONTROL TERMINAL DESIGNATIONS...................................................... 5
4WIRING EXAMPLES............................................................................................................ 6
4.1 0-10V OUTPUTS .................................................................................................................. 7
4.2 A1 –COOL.......................................................................................................................... 7
4.3 A2 –HEAT .......................................................................................................................... 7
4.4 A3 –FAN ............................................................................................................................ 7
4.5 TIME INTERVAL .................................................................................................................. 7
4.6 DIRECTION.......................................................................................................................... 7
4.7 MINIMUM VALUE................................................................................................................ 8
4.8 MAXIMUM VALUE (FAN A3) OUTPUT ONLY........................................................................ 8
4.9 BELIMO ™6WAY VALVE .................................................................................................. 8
4.10 2PIPE MODE ................................................................................................................... 8
5WIRING EXAMPLES – ANCILLARY FUNCTIONS ....................................................... 9
5.1 COMPLETE SYSTEM OVERVIEW .......................................................................................... 9
5.2 OCCUPANCY DETECTION .................................................................................................... 9
5.3 WINDOW CONTACT............................................................................................................. 9
5.4 FAULT INDICATION ........................................................................................................... 10
5.5 DOOR SWITCH................................................................................................................... 10
5.6 ENTERING OR EXITING THE ROOM. .................................................................................... 10
5.7 DOOR LEFT OPEN.............................................................................................................. 10
5.8 PIR INPUT ......................................................................................................................... 10
5.9 AUTOMATIC OCCUPANCY DETECTION LOGIC ................................................................... 10
5.10 USING THE SRC-131 IN AUTOMATIC OCCUPANCY MODE -(SCHOOL ROOM MODE) ..... 11
5.11 MANUAL OCCUPANCY INPUT ........................................................................................ 11
5.12 DOORBELL..................................................................................................................... 11
5.13 OUTSIDE DOOR STATION............................................................................................... 11
5.14 AUTOMATIC DAY SET TEMPERATURE ........................................................................... 11
5.15 REMOTE TEMPERATURE SENSORS.................................................................................. 12
5.16 MODBUS WIRING .......................................................................................................... 12
6INSTALLER OPTIONS MENU.......................................................................................... 13
6.1 NAVIGATING THROUGH THE INSTALLER MODE SETTINGS................................................ 13
6.2 OPTION LIST TABLE.......................................................................................................... 14
6.3 MODBUS DATA ................................................................................................................. 15
6.3.1 Data Format.............................................................................................................. 17
7SPECIFICATIONS............................................................................................................... 20

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1 Introduction
The SRC-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 understand and that functions in a logical manner. Further,
given the nature of the hospitality industry in general it is important that the thermostat be robust, flexible in
function and attractive. The SRC-131 thermostat has been designed with these important goals is mind.
The SRC-131 also offers advanced energy conservation features such as set point limit control, automatic
un-occupied heating and cooling settings as well as Modbus RTU communications for integration with the
“Building Automation System” (BAS) or “Hotel Check In” system. Additionally, the SRC-131 seamlessly
interfaces with the OC-3D occupancy detection system and HOT-242 “Door Station” system for added
functionality.
2 Controller Operation
The SRC-131is an extremely simple controller to operate and does not normally
require a user manual or user training.
The diagram to the left shows all LCD elements and the 6 buttons (Up / Down / Make
Up Room / Do Not Disturb / On – Off / Fan Mode.
Depending on switch and installer menu settings not all segments maybe shown.
On/Off
Tap the On/Off button to turn the thermostat On or Off and If permitted to select heat only or cool
only mode. (To ensure the simplest user operation on/off only Mode is set as default). Note - for simplicity - If
the thermostat is OFF by simply touching the thermostat display will turn it on.
Set Temperature
Adjust the target temperature with the Up or Down button. The range of temperature adjustment
can be limited with the installer setting “heat and cool limit setting”.
Fan
Single fan speed mode (Sw1=Off)
Tap the fan button to cycle between auto fan and continuous fan mode.
Three fan speed mode (Sw1=On)
Tap the fan button to cycle between low, medium, high and auto fan speeds. Press and hold the fan button
to turn the fan on continuously.
Note. Option 16 in the installer menu can set the SRC-131 to reset the indoor fan to Automatic Mode (cycle
on and off with heating and cooling) every time the controller is turned off.
Ventilation Mode
If permitted by DIP Sw7, the user can run the indoor fan only (Ventilation Mode) when the SRC-131 is off by
tapping the fan button. Each tap of the fan button will cycle between all available fan speeds.
“Make up Room” & “Do Not Disturb” Buttons
When enabled by DIP Sw8, pressing these buttons will activate relevant LCD segments and
backlight colour on the optional outside door station as well as write data to Modbus for monitoring
by a BAS system.

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3 Installation
3.1 System Design
Great effort has been taken to make the SRC-131 system intuitive, reliable and easy to install.
Using a common sense approach to the installation will ensure this product is installed easily and
to the customer’s satisfaction. Please read and understand this instruction manual so that installation,
testing and commissioning process is undertaken in an efficient and effective manner.
3.2 Opening Wall Controller
Open the SRC-131 wall controller by placing a flat blade screwdriver
or coin in the slot on the bottom of the thermostat case (1) and gently
twist (2) to release the case locking clip. Gently pry the two case halves
apart at the base taking care not to twist the case as this may crack the LCD.
3.3 Mounting Wall Controller
The SRC-131 should be mounted in a convenient location at approximately
1.2 to 1.5 meters from the ground. It should be located in a “typical” location
where it will sense the accurate room temperature and not be effected by
direct sunlight or drafts.
It is highly recommended that any penetrations in the wall where wiring may pass for example be sealed to
prevent drafts entering the rear of the thermostat and effecting the room temperature sensor.
3.4 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
Comp Protection Delay
5 Min Anti Cycle
Immediate Comp Start
Sw6
Klixon Mode
On
Off
Sw7
Ventilation Mode
Permitted
Not Permitted
Sw8
Door Station (Optional)
Fitted
Door Station Not Used
Note: The SRC-131 reads the switch settings on power up only. If you change any DIP switch settings
you must cycle power or press the reset button before these changes will take effect.
It is expected that only qualified people will make adjustment to these dip switch settings. Knowledge of the
HVAC system under the control of the SRC-131 is essential prior to making adjustment to these DIP switch
settings.
3.5 Wiring – HVAC Control Terminal Designations
Terminal
Function
C
24V Neutral
R 24V Active - This voltage is switched back through the relays
Hi Indoor Fan High Speed (NOT Used in Single fan speed mode - Sw 1 = OFF)
Med
Indoor Fan Medium Speed (NOT Used in Single fan speed mode - Sw 1 = OFF)
Low Indoor Fan Low Speed (Used in single & three fan speed mode)
Y Compressor or Cool - (Based on Sw2setting)
W - O/B Reversing Valve or Heat - (Based on Sw 2 setting)
A1 – Cool
0-10V Output for Cooling (Typically used to control modulating valves)
A2 – Heat 0-10V Output for Heating (Typically used to control modulating valves)
A3 – Fan 0-10V Modulating Output for Indoor DC Fan

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Com – 0V
0V terminal - Used for 0-10V, sensor or digital inputs ground reference
A Modbus Data A
B Modbus Data B
SI Remote temperature sensor input (Remote / average / Modbus data use)
DI
Digital (Switched input) for forced un-occupied or initiate doorbell function
WC Window Contact - Forces SRC-131 OFF if window open > 5 min (Adjustable)
DS Door Switch – Monitors room door status for occupancy detection (see page 11)
PIR
PIR ( Movement sensor) input for occupancy detection (see page 11)
The SRC-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 SRC-131 to function. The 24VAC applied to the SRC-131 “R”
terminal is switch back through the 2A relays to the equipment. Note the drawing provided here.
Caution - Although the SRC-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.
4 Wiring Examples

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Note - When the SRC-131 calls heating or cooling the SRC-131 will drive both the relays and the
0-10V outputs simultaneously. This way the SRC-131 can call a circulating water pump via the relays as it
controls room temperature with valves if needed.
4.1 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 SRC-131 has been fitted with 3 x 0-10V outputs.
The 0-10V outputs in the SRC-131 are PI (Proportional Integral) controlled. This control method provides the
most accurate and cost effective way to control heating and cooling valves by ensuring set temperate are reached
as quickly and efficiently as possible while reducing temperature overshoot.
As the SRC-131 is fitted with both relays as well as 0-10V outputs to control HVAC systems there may be some
slight disparity between the thermostat display and the 0-10V outputs actions. The SRC-131 displays the relay
actions more than the actions of the 0-10V outputs on the LCD. In most cases these are very closely matched
however as the 0-10v outputs have the capability of providing finer control than do the ON/OFF relays the
heating and cooling calls may have started slightly before indicated on the thermostat display. This is true of
the fan also.
4.2 A1 – Cool
This output is used to control a cooling valve.
4.3 A2 – Heat
This output is used to control a heating valve.
4.4 A3 – Fan
This output is used to control a variable speed fan or a variable
capacity AC system. If the fan mode is set to Auto speed the 0-
10V output will vary between these two values based on
calculated demand. If the user selects LOW speed, the 0-10V
output will be fixed at 3.3VDC, when Medium speed is selected the 0-10V output
will be fixed at 6.6VDC. High speed is set to 10VDC.
The installer menu provides the following settings for the control of the three 0-10V outputs.
4.5 Time Interval
Time interval sets the running average calculation time. The smaller the number the faster the 0-
10V output will respond to room temperature changes. Range is 10 – 300 seconds.
4.6 Direction
Forward action 0V = 0% open and 10V = 100% open; reverse action sets 0V = 100% open and 10V
= 0% open.

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4.7 Minimum Value
Rather than start the output at 0V, when the output is called it will immediately jump to this value. It will then
vary the output to maximum. When approaching set point the value will drop from the minimum value to 0v in 1
step. This setting is particularly useful for fan control as it will not permit the fan to run too slowly when close to
set point.
4.8 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.
These settings can be found in the installer menu.
4.9 Belimo ™ 6 Way Valve
Belimo™ manufactures an actuator that is in full cooling at 2V, off at 6V and full heating at 10V. To use this type
of actuator with the Smart Temp SRC-131 you must enter the installer menu and set valve type to “Belimo™
Mode”. The heating 0-10v output only is used in this mode
Information on the installer menu can be found on page 14 of
this manual.
As with normal valves, the 0-10V heating and cooling
span settings in the installer menu scale the heating and
cooling outputs. Factory default is full heating and full
cooling 1°C from set point. The heating and cooling span can
be adjusted independently to a maximum of full heating and
full cooling 3°C from set point. The output is linear.
Note When using “Belimo” ™ mode, both the A1 “cool” and the A2 “Heat” 0-10 output are used. Both will
provide the same output to the value. (The A3 “fan” output will remain unchanged and can be used to control a
DC fan or other devices).
4.10 2 Pipe Mode
The SRC-131 can measure water temperature via a sensor strapped to the water pipe and wired into the SRC-
131 Sensor input terminals (SI and Com 0-10 input). Based on the pipe temperature, the room temperature and
the set point the SRC-131 will control either the heating or the cooling outputs to maintain guest comfort.
When 2 pipe is mode is used, the SRC-131 will occasionally open the water valve to allow water flow within the
pipe so the SRC-131 can sample pipe temperature to determine / confirm operation mode.
If mode selection is permitted, the SRC-131 will only permit the appropriate mode to be selected based on the
pipe temperature.
To use the SRC-131 in 2 pipe mode set DIP 2 OFF and DIP 4 to the ON position. Set Installer menu
option 26 “Si & Com 0-V” to option “3” – 2 Pipe Mode.
The pipe sensor needed for 2 pipe mode is an external NTC sensor - available as an optional part.

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5 Wiring Examples – Ancillary Functions
Additional capabilities can be used when wiring the SRC-131 to external devices. These include BAS, room
occupancy detection systems, door card readers and the optional SyxthSense outside door stations.
5.1 Complete System Overview
As can be seen by the diagram to the left, the SRC-131 is the hub
of a sophisticated hotel room HVAC control and management
system.
Connecting the SRC-131 to an automatic occupancy detection system
such as the SyxthSense SRC-OC (optional) permits you to precisely
control HVAC energy consumption by automatically selecting a more
economical room set temperature when the room is unoccupied.
The optional door station connects quickly and easily to the SRC-
131. This provides the hotel guest with the ability to request
privacy or call for housekeeping when needed. A doorbell function is
also provided.
Network communications enables the room to be “turned on”
remotely as a guest arrives and “shut down” at checkout – further
saving money on energy costs.
Regardless of the need to control conferential HVAC systems, 2 or 4
pipe fan coils with modulating valves the SRC-131 has the necessary
outputs to achieve your control needs.
5.2 Occupancy Detection
The SRC-131 has sophisticated logicthat when
connected to your choice of movement sensors, door
and window switches will automatically control the set
point and mode of the SRC-131.
Using part or all of the functions described below
are completely optional. The SRC-131 will function
perfectly as a HVAC controller without the door, window
or occupancy detection logic enabled.
5.3 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 SRC-131 window input can be set for a Normally Open (switch open when window is closed) or normally
closed logic (switch closed when window is closed). When the window is left open for longer than the pre-set
time (0 to 300 seconds) the SRC-131 will automatically turn OFF. The text “OFF” will flash in the LCD to indicate
that the remote window (or door switch) is holding the SRC-131 in off mode. The wall controller will prohibit all
changes.
The SRC-131 will automatically restart once the window is closed.
The Installer menu option 28 “Window Input Logic” and option 29 “Window Input Delay” sets the window
detection logic in the SRC-131.

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5.4 Fault Indication
The SRC-131 can display the text “FLt” alternating with the temperature should you wish to alert the user of an
external fault with the heating or cooling system.
To enable this function enter the installer menu and set the Window contact input setting 31 to option 3. (See
page 16 for this setting). When the WC terminal and the Com-0V terminal are joined the SRC-131 will alternate
“FLt” with the current room temperature.
Register 32 will permit a time delay to be set after the fault signal is received if necessary to reduce false trips.
The fault indication has NO effect on thermostat function
5.5 Door Switch
The Door switch input (DS) is used by the SRC-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 SRC 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” sets the door detection logic in the SRC-131.
5.6 Entering or exiting the room.
Once the door is opened and then closed the SRC-131 will begin its occupancy detection process using the PIR
input described below. Based on the outcome of this process the SRC-131 will remain on and permit guest
interaction with the SRC-131 (adjust mode and set point for example), or switch to “un-occupied” mode where
the SRC-131 will substitute the guest set point and mode for the installer pre-set values.
5.7 Door Left Open
When the door is left open for longer than the pre-set time (0 to 300 seconds) the SRC-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 SRC-131 in off mode. This is done to prevent energy waste by trying to heat or cool an open room.
The SRC-131 will automatically restart once the door is closed.
5.8 PIR input
A PIR (passive infra-red) movement detector can be directly wired to the SRC-131 “PIR” input. As movement is
detected by the PIR it will send multiple On/Off pulses to the SRC-131 every time it detects movement. The
SRC-131 using this data along with door switch data will determine the occupancy status of the room and
behave accordingly. Note, the PIR must be separately powered, typically from a 12VDC supply.
5.9 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 SRC-131 instantly enters “Occupied Mode” where the SRC-131 will permit the
guest to set their desired temperature and mode of operation. Once the door is closed the SRC-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 SRC-131 will enter “Un-occupied mode” where the
guest’s temperature and mode will be replaced with installer pre-set values. Should movement be detected
within the installer pre-set seek time the SRC-131 will LOCK into “Occupied Mode” and no longer rely on
continued movement within the room to remain in “Occupied Mode”. Next time the door is opened and then
closed again the SRC-131 will again begin its occupancy detection process.
Note - even when the SRC-131 is in “un-occupied mode” it will continue to use the PIR input to determine room
occupancy. For example - a couple may be staying in the room and one leaves the room leaving the other
asleep in bed. As the door closes the SRC-131 will seek movement and when none is found it will enter “un-
occupied mode. As the sleeper wakes and then moves the SRC-131 will automatically re-enter “Occupied
Mode” even though it may have been some time since the door was closed.

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Installer option “PIR Input Delay” sets the PIR mode (On or Off) and the seek time value (1 to 15 minutes).
5.10 Using the SRC-131 in automatic occupancy Mode - (School Room Mode)
Wiring a PIR directly to the door switch input of the SRC-131 permits you to use the 131 to
automatically turn the Air conditioning on when a person enters the space (if seen by the movement detector)
and automatically turn if off again after a set period of time after they leave the space. Such as may be useful in
training rooms that are rarely occupied.
Steps to use the SRC-131 in automatic occupancy detection mode.
1. Wire the PIR movement detector into the DOOR SWITCH input.
2. Set the PIR input delay period 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.
5.11 Manual Occupancy Input
The DI (Digital Input) & Com 0-10 terminals within the SRC-131 can be used to instantly force the SRC-131 into
“Un-occupied Mode”. This input can be wired to a simple card reader or other 3rd party system that may be pre-
installed for room occupancy detection.
When the SRC-131 is in “Un-occupied Mode” the display will go completely blank except for the words
“Unoccupied” in the top left. 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.
5.12 Doorbell
A built in doorbell feature is included with the SRC-131 controller. This is normally activated by the optional door
station or via Modbus data link. In circumstances where this is not convenient, the digital input terminals can be
assigned as a doorbell switch with the digital input options detailed in the installer menu on page 11.
Simply place a momentary volt free switch across the S+ and S- terminals to activate the doorbell. Once
pressed, the doorbell will chime for 10 seconds.
5.13 Outside Door Station
When coupled with the optional SyxthSense door station the guest has the ability to set the room as “Do Not
Disturb”, call for housekeeping or be alerted to visiting guests with a pleasant doorbell chime. Hotel staff are
informed about the room status or guest’s needs by text information displayed on the door station LCD as
well as the door station backlight colours.
Connection between the SRC-131 and the hotel door
station is by the supplied 1 metre cable fitted with
RJ12 plugs. Longer cables up to 10 metres maximum
can be supplied at extra cost.
When fitting the door station, the SRC-131 DIP Sw8
must be ON. The outside door station will flash all LCD
segments if DIP Sw8 is in the wrong position.
5.14 Automatic Day Set Temperature
The SRC-131 can optionally reset the user set point and replace with an installer defined set point after the
SRC-131 has been off for more than 6 hours. This will typically happen after one guest has checked and
before the next guest checks in, but will not generally effect a guest who may turn the thermostat off for a few
hours or so or who may go out for the afternoon.
Option 40 in the installer menu defines this Function. Off or a value between 15 and 30c or 59-86F.

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5.15 Remote Temperature sensors
Occasionally the room controller cannot be installed in the ideal location to measure the room temperature
accurately. In these circumstances the SRC-131 can use optional remote temperature sensors. These are
a two wire device, not polarity dependent and simply wired into the SRC-131 sensor inputs terminals.
Depending on installer menu sensor settings, shown on page 11, remote sensor(s) will either override the
SRC-131 onboard sensor or average with the onboard sensor. Multiple sensors can be used for averaging
over larger areas if necessary. Wireless (RF) remote sensors are also available if wiring cannot be installed
economically.
5.16 Modbus Wiring
Modbus communications unlock many additional functions within the SRC-131 controller. It also permits
all modes, functions and controls to be remotely supervised and adjusted from a central location if
needed. Modbus object data can be found later on this manual.
The SRC-131 uses a high powered Maxim chipset that will “theoretically” permit the connection of up to 255
devices on a single Modbus node. RF noises and other interferences will reduce the real world permitted
connections to a maximum of 200 in most cases.
Modbus and other communication protocol rely on the quality of cable and good installation practises
to ensure reliable communications. Modbus requires the use of screen cable with the drain grounded in a
single location.
Hint! When the SRC-131 is connected to a working Modbus Network and receiving valid data, the
decimal point in the temperature display will blink. If there is no communication or the SRC-131 is
receiving corrupted data, this decimal point will remain on steady.
Modbus relies on a series connection and will normally not tolerate “Star” wiring or “T” branches.

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6 Installer Options Menu
The SRC-131 has an impressive list of options that can be installer selected. These options tune the
controller’s performance as well as set energy conservation settings. This menu is deliberately
hidden and difficult to enter to discourage unauthorised tampering.
The 2 steps to enter the installer menu are:
1. Ensure that the controller is OFF
2. Tap top left of the LCD, then tap top right of the LCD, then press and hold the centre of the LCD for 5
seconds.
6.1 Navigating Through The Installer Mode Settings
The bottom right button steps forward through the menu options, the bottom left button steps you
backwards.
Adjust your options with the up/down buttons.
Exit the menu saving changes by pressing and holding the bottom right (fan button) or waiting. The SRC-
131 will exit this menu automatically after 3 minutes.
The current menu option is shown between the left and right buttons. The
example to the right shows option 3, select deg C (option 0) or F display
(option 1).

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6.2 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
Note: If the mode button is hidden, the service and maintenance
staff can turn the SRC-131 on or off by pressing and holding the lower left of
the LCD for 15 seconds. 2 chirps indicates the SRC-131 has turned ON. 1
chirp indicates the SRC-131 has turned off (ver 3.03+)
1
Permitted Modes
0: Off / Auto
1: Off / Auto / Heat / Cool
2: Off / Heat /Cool
3: Off / Heat
4 Off / Cool
5: Off / Auto (Display current heating or cooling mode)
2
Room / Set display
0: Show room and set temp (default)
1: Show set temp only
3
Native display format
0: C (default) 1: F
4 C/F button shown on LCD 0: Off(default) 1: On
5
High temp set limit
5C-30C/41F-86F
6
Low temp set limit
5C-30C/41F-86F
7 Dead band 0C-5.0C/0F-10.0F 0.1C/0.1F steps
Data format : Dead band * 10
8 Fan Purge Period 0: OFF
1: Fan purge - 1 min
9 Fan span (3 speed relays) 0.5C-3.0C/1.0F-6.0F 0.1C/0.1F steps
Data format : Fan span * 10
10 0-10V Fan Interval (PI) 10-300 seconds 10 seconds steps (60 seconds default)
11 0-10V Fan direction 0: 0 - 10V – slow to fast
1: 10 to 0V – slow to fast
12 0-10V Fan minimum value
(minimum fan
0 -10V
Data format : 0-10V Fan minimum value * 10
13 0-
10V Fan Maximum value
(Maximum fan
0 -10V
Data format : 0-10V Fan minimum value * 10
14 Heat span 0.5C-3.0C/1.0F-6.0F 0.1C/0.1F steps
Data format : Fan span * 10
15 0-10V Heat interval (PI) 10-300 seconds 10 seconds steps (60 seconds default)
16 0-10V Heat direction 0: 10V is 100% open (forward acting)
1: 0V is 100% open n(reverse acting)
17 0-10V Heat
minimum
0 -10V
Data format : 0-10V Heat minimum value * 10
18
Cool span
0.5C-3.0C/1.0F-6.0F 0.1C/0.1F 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 acting)
1: 0V is 100% open n(reverse acting)
21
0-10V Cool
minimum
0 -10V
Data format : 0-10V Cool minimum value * 10
22
Auto Off Timer
0: No auto off timer
1-10hours 0.5 hour increments. Data format : hour * 10
23
Un-occupied heat
Set point
0: OFF
5C-30C/41F-86F 0.5C/1F steps
24
Un-occupied cool
Set point
0: OFF
5C-30C/41F-86F 0.5C/1F steps
25
Un –Occupied fan mode
Fan 3 Speed mode
1: Low (Auto) (default)

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26
Backlight
0: On with button press Only (Default > ver 3.1)
1: Always On high
27
TT sensor (SI & Com)
0: Remote – Use this sensor in place of the fitted sensor.
1: Average – Use both remote and fitted sensor and control to
28
Temperature Calibration
+/- 10 deg (C or F)
Adjust to show correct room temp.
29
Digital Input
0: Force Room to Unoccupied Mode
1: Chime Door Bell
30
Digital Input Logic
0: Normally Open
1: Normally Closed
31
Window Input Logic
0: Normally Open
1: Normally closed
32 Window Input Delay 0 - 300 seconds 30 seconds steps (30 seconds default)
33 Door Input Logic 0: Off (default)
1: Normally open
34 Door Input Delay 0 - 300 seconds 30 seconds steps (180 seconds default)
35 PIR Input Delay 0: Off (default)
1 – 15 minutes 1 minute steps (ver 3.3 changed 0-60min)
36 Reset Fan 0: Off
1: On
37 Belimo Mode 0: Off 1: On
38 Modbus Address 1-255
39 Baud rate 1: 4800bps
2: 9600bps (default)
40 Default Start Temp
Version 3.3+ 0=OFF (default) 15~35C or 59~86F
41 Beeper
Version 3.9+ 0: Off 1: On (default)
42 Factory Reset 0: NO
1:Yes (Exit to initiate)
6.3 Modbus Data
The SRC-131 has integrated Modbus RTU communications. Using a Modbus master controller such as the
SyxthSense Sedona SDC-32G+/20G+ many of the SRC-131 room controller features can be centrally
controlled and monitored.
Modbus is a simple protocol that is extremely popular due to its robustness and simple implementation.
It is also a “forgiving” protocol and will tolerate many installation errors. This being stated however, correct
wiring practices should be used to achieve maximum reliability. See earlier details on wiring Modbus networks.
The SRC-131 Modbus data is within the “40XXX” range, this being holding registers. Depending on your choice
of Modbus Master you may need to enter the address using the full address - such as “40012” or by selecting

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“Holding Registers” and entering the address simply as “12”.

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6.3.1 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
40001
Read Only
Device ID
Always Returns “131”
40002
Read Only
Firmware Version
Divide By 100 (e.g. Version 2.36 = 236)
40003
Read Only
DIP Switch
Settings
Binary Count
Sw 1 = 1, Sw2 = 2, Sw3 = 4, Sw 4 = 8 etc
40004 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
SRC-131in occupied mode.
40005 Read Only Bell Status 0 = Bell Is Silent
1 = Bell Is Chiming
40006 Read / Write Door Station
Status 0 = Normal - No Activity 1 = “Make Up Room” Active
2 = “Do Not Disturb” Active
40007
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)
40008 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
40009 Read / Write User Set Point Deg C = 0.5°C Steps
Deg F = 1°F Steps
Value / 10 ( e.g. 23.5°C = 235)
40010 Read / Write Contact
Reception
Notification
0 = Off
1 = Show Contact Reception on LCD
SRC-131LCD will flash “Contact Reception”
on LCD and sound chime. User may accept alert by touchi
ng
any button on SRC-131
40011
Read Only
Room
Temperature
Value / 10 (e.g. 21.7c = 217)
40012
Read / Write
Temperature
Display
0 = Show Room and Set Temperature
1 = Show Set Temperature Only
40013 Read/Write C/F Display 0 = Deg C format
1 = Deg F format
40014 Read / Write User Set Point
High Limit
5°C to 30°C Range (41°F-86°F) in 1°C/F Steps
1:1
40015 Read / Write User Set Point
Low Limit
5°C to 30°C Range (41°f-86°F) in 1°C/F Steps
1:1
40016
Read / Write
Dead Band
0.5°C to 5.0°C in 0.5°C Steps
1.0°F to 10.0°F in 1°F Steps
Value / 10 (e.g. 1.5°C Dead Band = 15)

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40017
Read / Write
Relay Span
0.5°C to 3.0°C in 0.5°C Steps
1°F to 10°F in 1°F Steps
Value / 10 (e.g. 1.0°C Span = 10)
40018 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 Min
10 = Cool Only Fan Purge - 3 Min
11 = Cool Only Fan Purge - 5 Min
12 = Cool Only Fan Purge - 10 Min
40019 Read / Write 0-10V Heat Span 0.5°C to 3°C in 0.5°C Steps
1°F to 6°F in 1°F Steps
Value / 10 (e.g. Heat Span of 1°C= 10)
40020 Read / Write 0-10V Cool Span 0.5°C to 3°C in 0.5°C Steps
1°F to 6°F in 1°F Steps
Value / 10 (e.g. Cool Span of 1°C = 10)
40021
Read / Write
Auto Off Timer
0 = 0ff
1 to 10 Hours.
Value / 10 (e.g. 3 Hour Auto Off Timer = 30)
40022 Read /Write Unoccupied Heat
Set Point 0 = Off 5°C to 30°C in 0.5°C Steps
41°F to 86°F in 1°F Steps
Value / 10 ( e.g. 17°C Unoccupied Heat = 170)
40023
Read / write
Unoccupied Cool
Set Point
0 = Off
5°C to 30°C in 0.5°C Steps
41°F to 86°F in 1°F Steps
Value / 10 ( e.g. 28.5°C Unoccupied Cool =
285)
40024 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
40025 Read / Write Backlight 0 = On With Button Press
1 = Always On (High)
2 = Always On Low - High With Button Press
40026
Read / Write
Remote
Temperature
Input Function
0 = Replace On Board Sensor With Remote
1 = Average Onboard Sensor With Remote
2 = Modbus Use Only (e.g. Coil Temp
Monitor)
40027
Read / Write
Digital Input
Function
0 = Occupancy Initiate
1 = Chime Door Bell
40028
Read / Write
Reset Fan Mode
0 = Leave Fan Mode Unchanged
1 = Reset Fan To Auto At Switch Off
40029 Read / Write Belimo Mode 0 = Standard 0-10V Valve Logic
1 = Belimo 6V = Off 3 Way Valve Logic
40030
Read / Write
Modbus Address
1 to 255
40031 Read / Write Baud Rate 1 = 4.8Kbs
2 = 9.6kbs
3 = 19.2Kbs
40032
Read Only
Digital Input
Status
0 = Open
1 = Closed
40033
Read Only
Internal Sensor
Value / 10 (e.g. 23.3°C = 233)

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Value
40034
Read Only
Remote Sensor
Value
Value / 10 (e.g. 21.8°C = 218)
40035
Read Write
W relay status
0 = Off (under thermostat control)
1 = Energised (under thermostat control)
1000 = Held OFF by Modbus
1001 = Held ON by Modbus
1 = Energised
40036 Read Write Y Relay Status 0 = Off (under thermostat control)
1 = Energised (under thermostat control)
1000 = Held OFF by Modbus
1001 = Held ON by Modbus
40037
Read Write
High Fan Relay
Status
0 = Off (under thermostat control)
1 = Energised (under thermostat control)
1000 = Held OFF by Modbus
1001 = Held ON by Modbus
40038
Read Write
Medium Fan
Relay Status
0 = Off (under thermostat control)
1 = Energised (under thermostat control)
1000 = Held OFF by Modbus
1001 = Held ON by Modbus
40039 Read Write Low Fan Relay
Status 0 = Off (under thermostat control) 1 = Energised (under thermostat control)
1000 = Held OFF by Modbus
1001 = Held ON by Modbus
40040 Read Write 0-10V Heat Value Value / 10 (e.g. 7.3V = 73)
( To write add 10 e.g. - to write 7.3v send 1073
40041
Read Write
0-10V Cool Value
Value / 10 (e.g. 7.3V = 73)
( To write add 10 e.g. - to write 7.3v send 1073
Values below only apply to version 2 hardware only, Firmware version 3+
40043
Read / Write
2 pipe mode
changeover
0 = Heat
1 = Cool
40044
Read / Write
Thermostat
Displaying
0 = Deg C
1 = Deg F
40045
Read / Write
Buttons shown on
display
0: Both mode and fan buttons show (default)
1: Show mode but hide fan button
2: Show fan but hide mode button
3: Hide both mode and fan buttons
40046 Read / Write Permitted Modes 0: Off / Auto
1: Off / Heat / Cool / Auto
2: Off / Heat / Cool
3: Off / Heat
4: Off / Cool
5: Off / Auto – (display current mode in LCD)
40047 Read / Write Swap C/F display
shown on display
0: C/F Button hidden
1: C/F button shown
40048
Read / Write
Fan Span for 3
speed relays
0.5C-10 C 0.5C step 1.0F-20 F 1F steps
Data format : Fan span * 10
40049
Read / Write
0-10 Fan Interval
10-300 seconds in 10 second steps (60 seconds
default.
40050
Read / Write
0-10 Fan Direction
0: 10V is 100% open (forward acting)
1: 0V is 100% open (reverse acting)
40051 Read / Write 0-10 Fan Minim
um
Voltage.
0-10v (Fan value x 10)
40052
Read / Write
0-10 Heat Interval
10-300 seconds in 10 second steps (60 seconds default.
40053
Read / Write
0-10 Heat
Direction
0: 10V is 100% open (forward acting)
1: 0V is 100% open n(reverse acting)

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7 Specifications
Input Voltage: 24VAC 50/60 Hz +/- 15%
Operating Temperature: 0°C to 50°C (32°F to 122°F)
Operating RH: 0-95% (Non Condensing)
Storage Temperature: 0°Cto 65°C (32°F to 150°F)
Size: 113 x 103 x 25mm.
Display Size: 69.5 x 46.3mm.
Backlight: White LED (Other Colours Available Upon Request)
Display Type: STN Touch Panel
Relay Rating: 30V @ 1Amp Max
0-10V Output Load: 10mA Max
Control Range: 5°C to 30°C (41°F to 86°F)
Memory Type: Non Volatile - Settings Do Not Require Battery Backup
Communications: Modbus RTU 4 .8K / 9.6K / 19.2 K, 1 Stop Bit, 8 Data Bits, 1 Start Bit. No Parity.
Plastic: ABS / Poly Blend – UV Stabilised and Fire Rated
Warranty: 2 Year RTB
SyxthSense Limited
3 Topsham Units
Dart Business Park
Exeter EX3 0QH
United Kingdom
Enquiries: T: 0844 840 3100 F: 0844 480 2200
Online store: www.syxthsense.com
Copyright 2012 SyxthSense Limited. All rights reserved.