aqotec RM360 via Modbus RTU Modbus Extension RS485
Monitors and controls an Aqotec RM360 district heating substation controller via Modbus RTU
Template for the Aqotec RM360 district heating substation controller via Modbus RTU over RS485. It reads temperatures, heat meter data, error statuses, and operating states for up to four heating circuits and hot water tanks. It also allows writing setpoints, modes, and correction values.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 98, read and write
- Brand
- Aqotec
- Key readings
- Outdoor and flow/return temperatures · Primary valve position · Heatmeter energy, power, and flowrate · HC1 to HC4 operating status and setpoints · Error bytes 1 to 4 · Heatmeter volume and serial number
- Available commands
- Main mode and HC1 to HC4 modes · HC1 to HC4 room setpoints and corrections · HC1 to HC4 outdoor switch-off temperatures · TC1 and TC2 hot water tank modes
- Compatible models
- RM360
- Last updated
Registers (98)
98 read, 29 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| sensorvalue T10 outdoor | °C | Read | |||
| sensorvalue T11 prim. return | °C | Read | |||
| sensorvalue T12 sec. flow temperature | °C | Read | |||
| sensorvalue T15 sec. return temperature | °C | Read | |||
| setpoint sec. flow temperature | °C | Read | |||
| calculated primary-valve position | % | Read | |||
| actual used return limitation | °C | Read | |||
| operating status | Read | ||||
| main mode | Read and write | ||||
| general-correction in reduction mode | K | Read and write | |||
| general-correction in heating mode | K | Read and write | |||
| Error-Byte 1 status | Read | ||||
| Error-Byte 2 status | Read | ||||
| Error-Byte 3 status | Read | ||||
| Error-Byte 4 status | Read | ||||
| Heatmeter energy in kWh | kWh | Read | |||
| Heatmeter actual power in kW | kW | Read | |||
| Heatmeter flowrate in l/h | l/h | Read | |||
| Heatmeter flow temperature | °C | Read | |||
| Heatmeter return temperature | °C | Read | |||
| Heatmeter serial number | Read | ||||
| Heatmeter volume in m³ | m³ | Read | |||
| Heatmeter error status (value vom heatmeter) | Read | ||||
| HC1 flow temperature setpoint | °C | Read | |||
| HC1 used room-setpoint | °C | Read | |||
| HC1 sensorvalue T17 return/room | °C | Read | |||
| HC1 status pump (P3) | Read | ||||
| HC1 operating status | Read | ||||
| HC1 room-setpoint | °C | Read and write | |||
| HC1 outdoor switch-off temperature in heating mode | °C | Read and write | |||
| HC1 outdoor switch-off temperature in reduction mode | °C | Read and write | |||
| HC1 mode | Read and write | ||||
| HC1 correction in heating mode | K | Read and write | |||
| HC1 correction in reduction mode | K | Read and write | |||
| HC2 outdoor switch-off temperature in heating mode | °C | Read and write | |||
| HC2 outdoor switch-off temperature in reduction mode | °C | Read and write | |||
| HC2 mode | Read and write | ||||
| HC2 correction in heating mode | K | Read and write | |||
| HC2 correction in reduction mode | K | Read and write | |||
| HC2 room-setpoint | °C | Read and write | |||
| HC2 status pump (P8) | Read | ||||
| HC2 operating status | Read | ||||
| HC2 sensorvalue T16 flow temperature | °C | Read | |||
| HC2 flow temperature setpoint | °C | Read | |||
| HC2 sensorvalue T20 return/room | °C | Read | |||
| HC2 used room-setpoint | °C | Read | |||
| HC3 outdoor switch-off temperature in heating mode | °C | Read and write | |||
| HC3 outdoor switch-off temperature in reduction mode | °C | Read and write | |||
| HC3 mode | Read and write | ||||
| HC3 correction in heating mode | K | Read and write | |||
| HC3 correction in reduction mode | K | Read and write | |||
| HC3 room-setpoint | °C | Read and write | |||
| HC3 status Pumpe (3P1) | Read | ||||
| HC3 operating status | Read | ||||
| HC3 sensorvalue 3TMP flow temperature | °C | Read | |||
| HC3 flow temperature setpoint | °C | Read | |||
| HC3 sensorvalue 3FBT return/room | °C | Read | |||
| HC3 used room-setpoint | °C | Read | |||
| HC4 correction in heating mode | °C | Read and write | |||
| HC4 correction in reduction mode | °C | Read and write | |||
| HC4 mode | Read and write | ||||
| HC4 correction in heating mode | K | Read and write | |||
| HC4 correction in reduction mode | K | Read and write | |||
| HC4 room-setpoint | °C | Read and write | |||
| HC4 status pump (4P1) | Read | ||||
| HC4 operating status | Read | ||||
| HC4 sensorvalue 4TMP flow temperature | °C | Read | |||
| HC4 flow temperature setpoint | °C | Read | |||
| HC4 sensorvalue 4FBT return/room | °C | Read | |||
| HC4 used room-setpoint | °C | Read | |||
| TC1 operating status | Read | ||||
| TC1 used setpoint for sensor top | °C | Read | |||
| TC1 sensorvalue T13 top | °C | Read | |||
| TC1 used start temperature for sensor top | °C | Read | |||
| TC1 used setpoint/switchoff temperature for sensor bottom | °C | Read | |||
| TC1 sensorvalue T14 bottom | °C | Read | |||
| TC1 used start temperature for sensor bottom | °C | Read | |||
| TC1 used charging temperature | °C | Read | |||
| TC1 status pump (P4) | Read | ||||
| TC1 mode hot water tank | Read and write | ||||
| HC3 status flow-switch from tapwaterstation | Read | ||||
| HC3 actual flow from tapwater station | l/min | Read | |||
| TC2 status pump (P5) | Read | ||||
| TC2 setpoint pumpe/valve (AO2) | % | Read | |||
| TC2 sensorvalue T23 top | °C | Read | |||
| TC2 sensorvalue T24 bottom | °C | Read | |||
| TC2 used charging temperature | °C | Read | |||
| TC2 hot water tank used setpoint for sensor top | °C | Read | |||
| TC2 hot water tank used start temperature for sensor top | °C | Read | |||
| TC2 hot water tank used setpoint/switchoff temperature for sensor bottom | °C | Read | |||
| TC2 hot water tank used start temperature for sensor bottom | °C | Read | |||
| TC2 operating status hot water tank | <v.> | Read | |||
| TC2 mode hot water tank | Read and write | ||||
| TC2 used setpoint buffer tank top | °C | Read | |||
| TC2 buffer tank used switchoff temperature botton | °C | Read | |||
| TC2 operating status buffer tank | Read | ||||
| HC7 sensorvalue 7TMP flow temperature | °C | Read | |||
| HC7 sensorvalue 7FBT return/room | °C | Read |
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Use cases
- Monitor outdoor, flow, and return temperatures on a live dashboard to verify district heating supply conditions.
- Track heat meter energy consumption and flow rates over time to validate billing data for building operators.
- Create alerts when error bytes indicate a fault condition on any of the four heating circuits.
- Adjust HC1 to HC4 room temperature setpoints remotely during seasonal commissioning without a site visit.
- Switch TC1 and TC2 hot water tank modes from the cloud to respond to occupancy changes or maintenance schedules.
- Log primary valve position data to diagnose control stability and detect hunting or stuck valve issues.
Installation
Connect the RS485 A and B terminals of the ModbusCloud Gateway to the corresponding RS485 terminals on the Aqotec RM360 controller.
Set the Modbus baud rate on the gateway to 19200 to match the RM360 default communication settings.
Configure a unique Modbus slave address on the RM360 and enter the same address in the ModbusCloud template settings.
Import the Aqotec RM360 Modbus RTU template into your ModbusCloud project from the template library.
Verify communication by checking that outdoor temperature and heat meter readings appear correctly on the cloud dashboard.
Confirm that float32 registers are read as two consecutive addresses and that the byte order matches the RM360 register map.
Things to watch for
Why are some temperature or energy readings showing incorrect or extremely large values?
The RM360 register map uses mixed data types including float32 values that span two consecutive addresses. Ensure the template is configured with the correct data type and byte order (typically big-endian) for each register. A mismatch will produce nonsensical values.
What baud rate should I use for the RS485 connection?
The RM360 communicates at 19200 baud by default. Make sure both the ModbusCloud gateway and the controller are set to the same baud rate, parity, and stop bit configuration.
Can I control all four heating circuits even if my installation uses fewer?
Yes. The template exposes HC1 through HC4, but unused circuits will simply return default or zero values. You can ignore or hide unused registers in the ModbusCloud dashboard.
How do I identify which fault has occurred using the error bytes?
The template reads error bytes 1 through 4 from the RM360. Refer to the official Aqotec RM360 controller documentation for the specific bit definitions and fault codes associated with each error byte.
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