Digital Thermostat X2

From the idea to the product

Based on our many years of experience in the field of individual room control, we have developed our own digital thermostat. During the development of the room controller, great emphasis was placed on important and useful functions. An in-house software development could offer corresponding flexibility. The ALM-X2 room controller is a single-room controller in an elegant design for mounting in a flush-mounted box. Appealing in design, convincing in its handling and function. The Digital Thermostat is ideal as a temperature controller for water-bearing underfloor heating. The controller measures the room temperature with the internal one and closes the heating contact when the setpoint temperature falls below the setpoint. The clear LCD display enables intuitive operation and creation of a daily program. The target value is divided into 24 hours in the daily program and can be defined independently for each day of the week. Data exchange with an MQTT broker makes the room controller a smart device and leaves nothing to be desired in terms of the available setting options.

Specifications

• Measured quantity: Temperature
• Power supply: 100~240VAC, 50/60Hz
• Max. switching capacity over L1: 5A resistive load, (3A) inductive load
• Power Consumption: Typ. <2W (230VAC)
• Switching difference: ±0.4ºC to ±2.0°C adjustable NC/NO or PI control
• Ambient temperature: 0..50°C
• Setpoint range / step size: 10..40°C / ±0.1 °C
• Wireless Technology: WiFi 2.4GHz | 802.11 b/g/n | 2412-2472MHz
• Radio protocol: Client Server protocol MQTT
• Sensor type internal: NTC 10K25°C B3950
• Housing / Degree of protection: ABS / IP20
• Connections: Screw terminal, max. 2.5 mm²
• Dimensions / Weight: 86 x 86 x 40mm (W x L x D) / 200g
• Mounting: Standard flush-mounted box (Ø=60 mm)
• Safety class: Class II

LCD display

The device has a clear and large LCD display with a white backlight. Already in the design, great importance was attached to intuitive operation via touch control. The display is clearly designed and the measured room temperature and the set set point can be determined at a glance. The display shows the minutes, the hours and the respective day of the week. There are 7 standalone daily programs that can be set.

The Digital Thermostat has a display accuracy of 0.1 degrees Celsius. The thermostat can be used in different rooms of a house or apartment with protection class IP20. The room thermostat display is divided into 4 main areas:

1. In the header area, time and date information including the key lock and WLAN status are displayed. Via a Wi-Fi connection, time information is automatically retrieved even after a power failure.
2. In the second area, the daily program with the temperature setpoint is displayed. The daily program is divided into 24 segments, which represents the 24 hours of a day. In total, the 7 working days make up the entire weekly program. When setting a setpoint, a distinction is made between a comfort temperature (for presence) and an ECO temperature (for absence). The comfort temperature can be set differently for each day of the week, but the ECO temperature is valid for all days of the week and can be changed under advanced settings. The Digital Thermostat is delivered from the factory with a weekly program that can be changed if necessary.
3. Below the daily program, the measured room temperature is displayed. In the right area, the Digital Thermostat displays the current status symbols. The division of the display thus enables an immediate reading of all relevant information.
4. In the footer area are the control buttons for controlling the room controller. There are a total of 5 buttons available that can be used to quickly make changes to the Digital Thermostat.

Digital Thermostat Features

Integration into smart home

The room controller is equipped with a wireless chipset and can be directly integrated into a WLAN network. There is no obligation to integrate the Digital Thermostat into a smart home system. However, it is recommended to at least integrate it into the home Wi-Fi network, so that the time no longer has to be set manually after a power failure, for example. Integrating data into a smart home system offers the advantage of having and managing the retrieval of data on a central system. The data exchange is based on the IoT protocol MQTT. The thermostat was designed for use in your own smart home such as Home Assistant, but can generally be used with any MQTT broker. The advantage of the Home Assistant is that the MQTT broker can be installed quite easily as an add-on and the thermostat configuration is automatically created in Home Assistant. It should be noted that only the standard functions of a room controller widget are supported in the respective smart home system.

The integration into your own WLAN network as well as parameterization is possible under the following Link Address described.

Mode Choice

The room controller supports both heating and cooling modes. For the cooling mode, the cooling function on your heat pump must also be activated. The sense of action of the switching contact is then reversed to the heating mode.

Keylock

The key lock can be used to avoid unwanted changes to the settings by children or strangers. To activate the key lock, the power button must be held for at least 3 seconds when it is switched on. An active key lock is indicated by the corresponding symbol on the display or by the flashing symbol if someone tries to press any button.

Switching difference and sensor calibration

The switching difference can be used to define the deviation value from which the switching contact should be closed or opened. This can be used to define the size of the hysteresis in the heating system. Hysteresis results from twice the value of the switching difference.

Sensor calibration can be used to correct the measured temperature value. Calibration should be carried out after 24 hours of continuous operation at the earliest so that final values are available.

Control mode

The room controller offers 2 control types to choose from:

1. Two-point regulator (recommended for water-bearing underfloor heating)
   A two-point controller is a proportional regulator and regulates according to the specified switching difference. If the room temperature falls below the set value and the switching difference, the switching contact is closed in heating mode. If the room temperature exceeds the set value plus the switching difference, the switching contact is opened in heating mode. Consequently, a hysteresis consisting of double the switching difference is used. A closed switch contact is represented by the active symbol "HEAT" in heating mode. The behavior in cooling mode is analogously inverting.

2. PI Regulator (Proportional-Integral Regulator)
   A PI regulator consists of 2 parts, a P part and an I part. The P portion is equivalent to the two-point controller described above and has a proportional effect. The I-component, on the other hand, does not have a fixed assignment between the setpoint value and the temperature deviation, but is also dependent on the duration of the deviation over time. The room controller tries to achieve the specified setpoint optimally, based on the PI algorithm. The PI parameters can be changed in the settings depending on the requirements.

Highlights

• Large LCD display with white backlight and touch buttons
• Clear display of the setpoint temperature and measured room temperature
• Displaying the time (minutes, hours, day of the week)
• Weekly program with 7 independent daily programs
• Definition of comfort and ECO temperature valid in the daily program
• Data preservation in the event of a power failure in the memory, time is automatically updated via WLAN
• Heating/cooling, switching difference, calibration, smart home integration via MQTT, and much more.

Scope of delivery

• Digital Thermostat X2 White for water-bearing underfloor heating
• 2 x Mounting Screws
• Data sheet (see also under TAB Download)

Please note that the display has double screen protectors and the bottom film is almost invisible!

Room thermostat warning

Electronic consumers may only be installed by appropriately qualified personnel.