The Siemens QMX3 series comprises wall-mounted sensors and room operator units designed for KNX PL-Link, KNX S-mode, and KNX LTE-Mode systems, particularly for Desigo™ Total Room Automation. These communicative devices offer a range of functions including temperature, CO2, and humidity measurement, as well as control over lighting, blinds, and scenes.
Function Description:
The QMX3 devices serve as versatile room operator units, integrating sensing and control capabilities. Depending on the specific model, they can measure room temperature, CO2 concentration, and relative humidity. They also provide control functionalities for various room elements such as lighting, blinds, and predefined scenes. Some models include a PID controller for room temperature or ventilation when operating in KNX S-mode.
For KNX PL-Link applications, the room automation station determines the functions of both the LCD display and keys. These units measure and indicate room temperature, humidity, and CO2, operate room functions, and display external information like outdoor temperature, outdoor humidity, or the state of a window switch.
In KNX S-mode, the devices measure and indicate room temperature, relative humidity, and CO2 concentration. They can also control relative humidity and CO2 concentration via threshold value switches, and room temperature using a PID controller. External information such as outdoor temperature, outdoor humidity, and window switch status can also be indicated.
The units feature an LCD display that shows room temperature, operating mode, and other relevant information. Labels for light, blinds, and scenes are exchangeable and can be created using a Word template. Operation is facilitated through 8 or 16 touchkeys.
Important Technical Specifications:
- Supply Voltage: KNX/PL-Link DC 21...30 V.
- Power Consumption (from room automation station):
- QMX3.P02, QMX3.P30, QMX3.P34, QMX3.P40: Max 7.5mA at DC 24 V
- QMX3.P44, QMX3.P37: Max 10mA at DC 24 V
- QMX3.P70, QMX3.P74: Max 15mA at DC 24 V
- Temperature Sensor (all types):
- Measuring element: NTC resistance sensor
- Measuring range: 0...50 °C
- Measuring accuracy (5...30 °C): ±0.8 K
- Measuring accuracy (25 °C): ±0.5 K
- Relative Humidity Sensor (QMX3.P40, QMX3.P44, QMX3.P74, QMX3.P70):
- Measuring range: 10%...95% r.h.
- Accuracy (20%...80%): ±4% at 25°C
- Accuracy (0%...20%, 80%...95%): ±6% at 25°C
- CO2 Sensor (QMX3.P74, QMX3.P70):
- Measuring range: 400...10000 ppm
- Measuring accuracy at 23 °C and 1013 hPa for 400...2000 ppm: ±(30 ppm +4% of measured value)
- Temperature dependency: ±2 ppm / °C typical
- Pressure dependency: 0.14% of measured value / hPa
- Long-term drift: ±20 ppm per year
- Service life: 15 years
- Ports/Interfaces: KNX/PL-Link, 9.6 kbps baud rate. Uses solid conductors (2-core, twisted pair) with a wire diameter of 0.8 mm to max. 1.0 mm. Single cable length from room automation station to room is <1000 m.
- Housing Protection: IP 30 as per EN 60529.
- Insulation Protection Class: III.
- Environmental Conditions (Normal Operation):
- Temperature: 0...50 °C
- Humidity: < 85% rh
- Mechanical conditions: Class 3M2
- Environmental Conditions (Transport):
- Temperature: -25...70 °C
- Humidity: < 95% rh
- Mechanical conditions: Class 2M2
- Dimensions: The devices are designed for wall-mounting. Recommended height for installation is 1.50 m above the floor.
- Weight: Operator unit weights vary by model (e.g., QMX3.P02: 91g, QMX3.P74: 132g). Total weight with base plate and packaging ranges from 168g to 216g.
Usage Features:
- Plug & Play Functionality (KNX PL-Link): Room operator units receive power from the connected room automation station via the KNX PL-Link interface. This interface supports plug & play functionality for pre-configured devices. Electrical installers typically install only the base plate and the KNX PL-Link plug.
- Commissioning:
- KNX PL-Link: Commissioning is done via the room automation station using the SSA-DNT or ABT tool. Manual commissioning involves pressing specific keys on the unit to enter programming mode, allowing the tool to identify and assign the device.
- KNX S-mode: Engineering and commissioning are performed using the ETS tool.
- KNX LTE-Mode: Engineering and commissioning are performed using the ACS tool.
- Labeling: Labels for switches (QMX3.P02, P37) can be created using a Word template, printed on transparency film, and inserted into the device.
- Display Layout: The segment LCD displays room temperature, humidity, CO2, setpoint adjustment, control mode (fan, operating mode), navigation, and presence/comfort prolongation.
- Key Functions: Keys allow for toggling between indoor/outdoor measurements, adjusting setpoints, controlling fan speed, changing room operating modes, and activating comfort prolongation. An arrow on the display indicates an operable element.
- LED Indicators:
- A red service LED on the back indicates programming mode.
- Green Leaf (green, red) indicates energy efficiency.
- Green, orange, red LEDs indicate air quality (for multi-sensor QMX3.P70).
- Each key is equipped with a green LED to indicate switch state.
- CO2 Sensor Notes: The CO2 sensor uses infrared absorption measurement (NDIR) and is maintenance-free due to a built-in self-correcting ABC (Automatic Baseline Correction) algorithm. This algorithm tracks the sensor's lowest reading over 8 days and corrects for drift. The specified accuracy is reached after 25 days of continuous operation.
Maintenance Features:
- Cleaning: The device can be cleaned with off-the-shelf, solvent-free cleaning agents. Only a soft, damp cloth should be used; mechanical aids (rough sponges) are not recommended.
- Reset to Factory Setting: A long press (>20 s) on the programming pin (or specific keys for units with display) will reset all user preference data and configuration settings to factory default. This operation is irreversible.
- Installation Considerations:
- Avoid mounting devices in recesses, shelves, behind curtains or doors, or above/near heat sources to prevent inaccurate sensor readings.
- Avoid direct solar radiation and drafts.
- Seal conduit boxes or installation tubes to prevent air currents from affecting sensor readings.
- For wall-mounting, ensure a distance of 30 mm (from above) / 20 mm (from below) to the base plate for proper device snapping.
- The optional metal-reinforced base plate QMX3.MP1 provides rigidity and includes a removable gray foam plate to compensate for the jutting edge of cavity wall boxes.
- Wiring: Wires are not interchangeable. The device is protected against faulty wiring, but interchanged wires will prevent communication. The KNX / KNX PL-Link bus must not be connected to the tool plug.
- Safety: Devices with CO2 measurement are not suitable for safety applications such as gas or smoke alarms. The devices are not protected against accidental connection to AC 230 V.
- Disposal: The device is considered electrical and electronic equipment and must be disposed of through designated channels, complying with all local and applicable laws and regulations.
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