KL Lufttechnik KL 170-350-500

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

1. 1Connect the Modbus gateway to the KL ventilation unit using RS485 wiring (A, B, GND) for RTU, or via the Ethernet port for Modbus TCP.
2. 2Set the Modbus device address on the KL unit to 10, or match it to your gateway configuration.
3. 3If 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.
4. 4For RTU connections, configure the gateway serial port to match the baud rate and parity settings of the KL unit.
5. 5Import the KL Lufttechnik KL 170-350-500 template in the ModbusCloud platform and assign it to the gateway.
6. 6Verify that live readings such as supply temperature and fan speed appear on the dashboard before completing the installation.

Things to watch for

01

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.

02

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.

03

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.

04

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.

Registers (26)

25 read / 10 write

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