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Designer Range Modbus Room Thermostats | SRT-50-MOD-M Touchscreen LCD Room Thermostat, Modbus, 90-250Vac Power Supply

SRT-50 are attractive flush mounted thermostats with a large colour intuitive 3.5” touchsreen for viewing the system status and modifying the settings. The SRT thermostats are suitable for wide variety of applications.. The 320x480 pixel 255K touchscreen provides a dynamic sharp graphical interface to the heating and cooling control. The SRT thermostats can be used with stand-alone applications as well as with networked BACnet and Modbus systems (select the correct thermostat model).

The SRT-50-xx-24 models come with 24Vac/dc power supply. The SRT-50-xx-M models come with 90-250Vac/dc power supply i.e. they can be connected directly to the building Live and Neutral connections. The SRT-50-xx-12 models come with 12Vdc power supply allowing them to be used in caravans, boats and other installations where only 12Vdc power cirucit is available.

The thermostats are normally switching directly boiler, chilerr etc plants via a built-in 7A 230Vac rated relay. The BACnet MS/TP and Modbus models can be used as a network thermostat for home and building automation systems. In system applications the thermostat can also be used to switch the Lighting and/or Air-Conditioning on/off. As the modern buildings, houses and apartments require ever more comfort features to SRT Touchscreen thermostats can act as an important part of the system providing attractive interface to the control.

The SRT-50 touchscreen thermostats are also suitable for stand-alone installations where the thermostat is used to replace the existing "non-intelligent" thermostats such basic Honeywell, Sunvic, Drayton and Sunvic models. Using the SRT touchscreen range the system is upgraded for a state-of-the art interface with many energy saving features. The energy saving features include Cleaning Mode where the system is switched of for a timed period. This can be activated via e.g. window contact or manually from the thermostat. In system installations the cleaning mode can also be activated automatically over the BACnet or Modbus network.

The SRT-50 thermostats have heating and/or cooling control with accurate adjustable hysteresis to the 0.1degrees. The display shows visually at glace - using modulating heating and cooling 'feature ring' - the difference between the target setpoint and the current temperature.

The SRT-50 touchscreen thermostats have range of comfort features to guarantee the optimal conditions in the room space. The built-in Boost button switches the system on for a specified period, allowing the heating to be switched on e.g. on arrival to the space. The SRT-50 touchscreen thermostats feature a remote sensor input for underfloor heating minimum and maximum control. When the floor tmeperature exceeds a set temperature the thermostat switches the relay output off protecting the floor surface. If the floor temperature drops below a minimum setting in the heating mode, the heating is forced automatically on. This allows the SRT thermostats to be used e.g. in bathrooms where the floor temperature is kept at the level comfortable for bare feet. In the cooling mode the minimum temperature can switch off the relay i.e. protect the system from condensation.


The SRT-50 touchscreen thermostats feature also an ECO mode, that allows the temperature to operate under reduced setpoint (heating mode) or increased setpoint (cooling mode) to reduce the energy consumption automatically during the unoccupied/night periods. The mode can be automatically activated over the BACnet or Modbus communication network, or via the digital volt-free input.


The SRT-50 touchscreen thermostats have built-in holiday mode. Upon the activation of the holiday mode, the thermostats is switched to a reduced setpoint for a specified period. The holiday mode can also be activated over the BACnet or Modbus interface.


The built-in frost protection is always active offering building fabric protection during the off or holiday periods.


  • Wide Range of Power Supply Options; 12Vdc, 24Vac/dc or 90-250Vac/dc
  • 3.5” Colour Responsive Resistive Touchscreen, 320 x 480 Pixels
  • Traditional 'Stand-Alone' Heating/Cooling Thermostats Functionality
  • BACnet and Modbus Models for a part of Smart System
  • Flush mounted to the UK or European Wall Mounting Box; Attractive
  • Modern Designer Look with Black/Chrome Colour Scheme
  • Attractive Simple to Use Graphical User Interface (GUI)
  • Feature Ring Advising when Heating or Cooling Required
  • Heating and/or Cooling Control
  • ECO mode Energy Savings (reduced setpoint)
  • Boost Mode for Boosting the thermostat ON e.g on arrival for a timed period
  • Timed Cleaning Mode for Energy Saving and Space Cleaning
  • Automatic Frost Protection to protect building fabric
  • Remote NCT10 Control Sensor Input
  • Underfloor NTC10 Sensor Input for Min/Max temperature control; protects floors from overheating. When used in bathrooms, maintains comfort temperature to feet.
  • Lockable Screen with 4-Digit Lock Code
  • Number of Lock Screen Options depending on the Applications
  • Maintenance Mode Password Protected
  • BACnet MS/TP Communication Models (-BAC)
  • Modbus RTU Communication Models (-MOD)
  • Air-Conditioning and Lighting Enable Buttons in System Application via the Network
  • Suitable for Landlord Applications with Lock Screens and Configurable Display Options
  • Humidity Sensor Option for Internal Humidity Display and Monitoring

Features Suitable for Landlord Thermostat Applications:-

The SRT thermostats are also suitable for Landlords providing controlled energy savings and include functionality such as below that are particularly suitable for landlord applications.

  • The maximum and minimum temperature adjustments can be limited
  • Possible to lock the thermostat remotely via Modbus or BACnet
  • Multiple Lock Modes e.g. Locking the Setpoint Adjustment or Locking Completely
  • Possible to restrict functions e.g. disable the boost mode
  • 4 digital adjustable LOCK code and 4 digit adjustable MAINTENANCE MODE code

Modbus and BACnet Networking Examples:-

The SRT BACnet touchscreen thermostats and Modbus thermostats thermostats can be linked to building automation and home automation systems. The industry standard BACnet and Modbus protocols guarantee interoperability to most home automation systems such as Crestron and Control4, as well as building automation and control systems such as Trend, Tridium, Honeywell, Alerton, Priva and SyxthSense Sedona solutions. Connecting SRT BACnet and Modbus thermostats to these systems release the full potential of the attractive user interface with system functionality. The standard Modbus and BACnet implementation guarantee interoperability.

SRT Modbus and BACnet networking Examples

Select from SRT-Relative-Humidity-Option:
Relative Humidity Option for SyxthSense Touchscreen Range
Select from Enclosure-Colour-Option:
White Colour Enclosure Option RAL9010