Meltem M-WRG-S
Controls Meltem ventilation systems via RS485 Modbus RTU
Template for the Meltem M-WRG-S ventilation system using Modbus RTU over RS485. It enables monitoring and control of ventilation functions through a ModbusCloud gateway at 9600 baud.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 0, read only
- Brand
- Meltem
- Compatible models
- M-WRG-S
- Last updated
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Use cases
- Monitor ventilation operating status and fan speed remotely from the ModbusCloud dashboard.
- Adjust ventilation levels for individual Meltem M-WRG-S units without visiting the site.
- Create alerts when a ventilation unit stops responding or reports a fault condition.
- Track historical ventilation data across multiple apartments or rooms in one building.
- Schedule ventilation mode changes based on occupancy patterns or time of day.
Installation
Connect the ModbusCloud Gateway to the Meltem M-WRG-S RS485 terminals using a twisted pair cable, observing correct A/B polarity.
Set the baud rate on both the gateway and the M-WRG-S to 9600, with matching parity and stop bit settings.
Assign a unique Modbus slave address on each Meltem M-WRG-S unit connected to the RS485 bus.
Enable Modbus RTU communication on the M-WRG-S unit via its configuration menu or DIP switches, as described in the Meltem installation manual.
Import the Meltem M-WRG-S template in the ModbusCloud platform and assign it to the gateway, entering the correct slave address for each unit.
Verify communication by checking live data on the ModbusCloud dashboard and confirming that control commands are accepted by the unit.
Things to watch for
The gateway cannot communicate with the Meltem M-WRG-S. What should I check?
Verify that the RS485 wiring polarity (A and B) is correct and that both devices use identical serial settings: 9600 baud, same parity, and same stop bits. Also confirm that Modbus RTU is enabled on the ventilation unit.
Can I connect multiple Meltem units to one ModbusCloud gateway?
Yes. Use a daisy-chain RS485 bus topology and assign a unique Modbus slave address to each M-WRG-S unit. Add a separate template instance in ModbusCloud for each address.
Do I need a termination resistor on the RS485 bus?
For short cable runs with only one or two units, termination is often not required. For longer runs or buses with many devices, place a 120 ohm termination resistor at each end of the bus to reduce signal reflections.
Which firmware version is required on the Meltem M-WRG-S for Modbus support?
Refer to the Meltem product documentation for your specific hardware revision. Some older units may need a firmware update to enable the Modbus RTU interface over RS485.
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