KL Lufttechnik KL 170-350-500
Controls KL Lufttechnik ventilation systems via Modbus TCP or RTU.
Template for KL Lufttechnik KL 170, KL 350, and KL 500 ventilation units via Modbus TCP or RTU. Reads temperatures, air quality, fan speeds, and filter status. Allows control of operating mode, fan levels, room setpoint temperature, and ventilation intensity.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 26, read and write
- Brand
- KL Lufttechnik
- Key readings
- Supply/extract/room temperatures · VOC value and relative humidity · Fan speeds (supply and extract) · Current air level and operating mode · Filter remaining life and alerts · Error ID, SubID, and flag
- Available commands
- Operating mode and manual fan level · Room temperature setpoint · Intensive ventilation and base ventilation · Air level offset LS1/LS2
- Compatible models
- KL170 · KL350 · KL500
- Last updated
Registers (26)
25 read, 10 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Temperatur Zuluft | °C | Read | |||
| Temperatur Abluft | °C | Read | |||
| Temperatur Lufteintritt vor Wärmetauscher | °C | Read | |||
| Aktuelle Luftstufe | Read | ||||
| Aktuelle Drehzahl Ventilator Zuluft | rpm | Read | |||
| Aktuelle Drehzahl Ventilator Abluft | rpm | Read | |||
| Restlaufzeit Gerätefilter | — | Read | |||
| Filtermeldung Gerätefilter | Read | ||||
| Luftstufe im Manuellbetrieb | Read and write | ||||
| Grundlüftung | Read and write | ||||
| Intensivlüftung | Read and write | ||||
| Betriebsart | Read and write | ||||
| VOC Wert | ppm | Read | |||
| Relative Feuchte | % | Read | |||
| FehlerID | Read | ||||
| FehlerSubID | Read | ||||
| FehlerFlag | Read | ||||
| Restdauer Intensivlüftung | min | Read | |||
| Sensorempfindlichkeit | Read and write | ||||
| Solltemperatur Raum | °C | Read and write | |||
| Luftstufenverschiebung LS1 | Read and write | ||||
| Luftstufenverschiebung LS2 | Read and write | ||||
| Restlaufzeit Außenfilter | Read | ||||
| Filtermeldung Außenfilter | Read and write | ||||
| Aktuelle Temperatur Raum | °C | Read | |||
| Filterwechsel Gerätefilter | Write |
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Use cases
- Monitor supply, extract, and room temperatures on a live dashboard to verify ventilation performance.
- Create an alert when filter remaining life drops below a threshold so maintenance can be scheduled proactively.
- Control operating mode and fan level remotely to adjust ventilation intensity without an on-site visit.
- Set up a notification when an error flag is raised, enabling faster remote fault diagnosis.
- Log VOC and humidity values over time to document indoor air quality for building reports.
- Adjust the room temperature setpoint from the cloud during seasonal changes or tenant requests.
Installation
Connect the Modbus gateway to the KL ventilation unit using RS485 wiring (A, B, GND) for RTU, or via the Ethernet port for Modbus TCP.
Set the Modbus device address on the KL unit to 10, or match it to your gateway configuration.
If no physical control panel is connected, use the KL configuration software to deactivate the panel and enable Modbus communication, otherwise the unit will display an error.
For RTU connections, configure the gateway serial port to match the baud rate and parity settings of the KL unit.
Import the KL Lufttechnik KL 170-350-500 template in the ModbusCloud platform and assign it to the gateway.
Verify that live readings such as supply temperature and fan speed appear on the dashboard before completing the installation.
Things to watch for
The ventilation unit shows an error and does not respond to Modbus commands. What is wrong?
If no physical control panel is connected, the panel must be deactivated using the KL configuration software. Without this step the unit enters an error state and ignores Modbus communication.
Some register values do not match expected readings, such as humidity or base ventilation.
Register addresses changed between firmware versions. Relative Humidity moved from register 708 to 707, and base ventilation moved from 707 to 309. Check your firmware version and update the template registers accordingly.
Can I use Modbus TCP instead of RTU?
Yes, both protocols are supported. The unit ships with Modbus RTU as default. To switch to Modbus TCP, use the KL configuration software to change the communication mode.
What is the default Modbus device address?
The default device address is 10. You can change it in the KL configuration software if your installation requires a different address.
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