Alde Heating System LIN Protocol
Frame Overview
Alde heating systems use two main LIN frame types for communication:
| Frame Type | LIN ID | Purpose |
|---|---|---|
| Control Frame | 0x1A | Send commands and setpoints |
| Info Frame | 0x1B | Report status and temperatures |
Control Frame (ID 0x1A)
Frame Layout:
| Byte | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| Content | 0x00 | 0x00 | 0x00 | Control Byte 1 | Control Byte 2 | Control Flags | 0xFF | 0xFF |
| Purpose | Reserved | Reserved | Reserved | Zone 1 Temp + Gas | Zone 2 Temp + Power | System Flags | Reserved | Reserved |
Bytes 0-2: Fixed Values
Always [00] [00] [00] - reserved/unused
Byte 3: Control Byte 1
| Bit Range | Field | Values |
|---|---|---|
| 0-5 | Zone 1 temperature setting | Temp=(value × 0.5) + 5.0°C |
| 6 | Gas heating enable | 0=Disabled, 1=Enabled (use propane/gas for heating) |
| 7 | Gas valve enable | 0=Valve closed, 1=Valve open (enables gas flow to heater) |
Temperature Formula: Range 5°C-30°C (0x00-0x32), Example: 19°C = 0x1C
Byte 4: Control Byte 2
| Bit Range | Field | Values |
|---|---|---|
| 0-5 | Zone 2 temperature setting | Temp=(value × 0.5) + 5.0°C |
| 6-7 | Electric heating power level | Off=0, 1kW=1, 2kW=2, 3kW=3 |
Temperature Formula: Range 5°C-30°C (0x00-0x32), Example: 19°C = 0x1C
Byte 5: System Control Flags
| Bit Range | Field | Values |
|---|---|---|
| 0 | Main panel on/off | 0=Off, 1=On |
| 3-4 | Hot water heating mode | 00=Off, 01=Normal, 10=Boost, 11=Auto |
| 6 | AC automatic mode | 0=Manual, 1=Automatic |
Bytes 6-7: Reserved
Fixed values [FF] [FF] - unused in current implementation.
Info Frame (ID 0x1B)
Frame Layout:
| Byte | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| Content | Zone1 Temp | Zone2 Temp | Outdoor Temp | Control Byte 1 | Control Byte 2 | System Status | Reserved | Reserved |
| Purpose | Measured | Measured | Measured | Zone 1 Target + Gas Flags | Zone 2 Target + Electric Power | System flags | - | - |
Byte 0: Zone 1 Current Temperature
| Value Range | Temperature | Description |
|---|---|---|
| 0x00-0xFA | -42°C to +83°C | Temperature = (value × 0.5) - 42.0°C |
| 0xFB | < -42°C | Below sensor range |
| 0xFC | > 83°C | Above sensor range |
| 0xFD | – | No temperature sensor detected |
| 0xFE | – | Not used |
| 0xFF | – | Invalid reading |
Byte 1: Zone 2 Current Temperature
| Value Range | Temperature | Description |
|---|---|---|
| 0x00-0xFA | -42°C to +83°C | Temperature = (value × 0.5) - 42.0°C |
| 0xFB | < -42°C | Below sensor range |
| 0xFC | > 83°C | Above sensor range |
| 0xFD | – | No temperature sensor detected |
| 0xFE | – | Zone unused/not installed |
| 0xFF | – | Invalid reading |
Note: Zone 2 is always present in the protocol frame but may indicate “unused” (0xFE) or “no sensor” (0xFD) on single-zone Alde units.
Byte 2: Outdoor Temperature
| Value Range | Temperature | Description |
|---|---|---|
| 0x00-0xFA | -42°C to +83°C | Temperature = (value × 0.5) - 42.0°C |
| 0xFB | < -42°C | Below sensor range |
| 0xFC | > 83°C | Above sensor range |
| 0xFD | – | No temperature sensor detected |
| 0xFE | – | Not used |
| 0xFF | – | Invalid reading |
Byte 3: Control Byte 1
Temperature Setpoint (Bits 0-5):
| Value Range | Temperature Setting | Description |
|---|---|---|
| 0x00-0x32 | 5°C - 30°C | Current setpoint |
| 0x3B | < 5°C | Below minimum |
| 0x3C | > 32°C | Above maximum |
| 0x3D | – | Sensor error |
| 0x3E | – | Unused |
| 0x3F | – | Invalid |
Status Bits (6-7):
| Bit Range | Field | Description | Values |
|---|---|---|---|
| 6 | Gas Heating Status | Gas heating active | 0=Inactive, 1=Active |
| 7 | Gas Valve Status | Gas valve state | 0=Closed, 1=Open (gas flowing) |
Byte 4: Control Byte 2
Same format as Byte 3 for Zone 2, plus:
- Bit 6-7: Electric power level
00= Off01= 1 kW10= 2 kW11= 3 kW
Byte 5: System Status Flags
| Bit Position | Function | Values |
|---|---|---|
| Bit 0 | Panel on | 0=Off, 1=On |
| Bit 1 | Panel busy | Communication status |
| Bit 2 | Error present | 0=OK, 1=Error condition |
| Bit 3-4 | Water mode | 00=Off, 01=Normal, 10=Boost, 11=Auto |
| Bit 5 | AC input available | AC power status |
| Bit 6 | AC Auto mode | Automatic operation |
| Bit 7 | Pump running | Circulation pump active |
Bytes 6-7: Reserved
Currently unused in this frame format.
Communication Example
Setting Zone 1 to 19°C, Zone 2 to 20°C, Gas On, Electric Power 2kW
Control Frame (0x1A):
[00] [00] [00] [0x5C] [0x9E] [0x01] [FF] [FF]
Byte 3: 0x5C = 19°C setpoint (0x1C) + Gas on (system-wide)
Byte 4: 0x9E = 20°C setpoint (0x1E) + Electric 2kW (system-wide)
Byte 5: 0x01 = Panel on
Reading Current Status
Info Frame (0x1B) Response:
[0x7A] [0xFE] [0x39] [0x62] [0x00] [0x81] [FF] [FF]
Byte 0: 0x7A = Zone 1 actual: 19°C
Byte 1: 0xFE = Zone 2 actual: Zone unused/not installed
Byte 2: 0x39 = Outdoor: 15°C
Byte 3: 0x62 = Zone 1 setpoint: 22°C, Gas active
Byte 4: 0x00 = Zone 2 off
Byte 5: 0x81 = Panel on, Pump running