Command 0xC9: Base Capabilities
This command is used to retrieve base capability information from a heat pump. This command response is used to check whether certain features exist on any given unit, and is used to self-configure units accordingly.
| Byte | Purpose | Possible Values | Supported by mUART | Notes |
|---|---|---|---|---|
| 0 | CommandType | 0xC9 | ||
| 1-6 | "Arbitrary Data" | 0x03 | ||
| 7-15 | Unit Capabilities | See below |
Unit Capabilities
| Byte | Bitmask | Purpose | Notes |
|---|---|---|---|
| 7 | 0x01 | ??? | Observed true |
| 7 | 0x02 | Heat Disabled (if true) | |
| 7 | 0x04 | ??? | Observed true |
| 7 | 0x08 | ??? | |
| 7 | 0x10 | Fan Bit A | |
| 7 | 0x20 | Vertical Vane support | |
| 7 | 0x40 | Vane swing support | Seems to cover both vane types, if horizontal vane exists. |
| 7 | 0x80 | ??? | |
| 8 | 0x01 | Dry function disabled (if true) | |
| 8 | 0x02 | Fan function disabled (if true) | |
| 8 | 0x04 | Has extended temperature range | Seems to determine if the A-scale is usable. |
| 8 | 0x08 | Fan Bit B | |
| 8 | 0x10 | Automatic Fan Speed disabled (if true) | |
| 8 | 0x20 | Installer Settings (Function) support | |
| 8 | 0x40 | Test Mode support | |
| 8 | 0x80 | Supports dry temperature | |
| 9 | 0x01 | Has status display | |
| 9 | 0x02 | Fan Bit C | |
| 9 | 0x04 | ??? | Observed true and false |
| 9 | 0x08 | ??? | |
| 9 | 0x10 | ??? | Observed true and false |
| 9 | 0x20 | Supports Outside Temp Reporting | Unconfirmed, possibly JP units only. |
| 9 | 0x40 | ??? | |
| 9 | 0x80 | ??? | Observed true and false |
| 10 | All | Minimum cool/dry temp setpoint | |
| 11 | All | Maximum cool/dry temp setpoint | |
| 12 | All | Minimum heating temp setpoint | |
| 13 | All | Maximum heating temp setpoint | |
| 14 | All | Minimum auto temp setpoint | |
| 15 | All | Maximum auto temp setpoint |
Bytes 10-15 appear to only be sent if the extended temperature range is supported by the unit.
Determining Fan Speeds
The number of allowed fan speeds is determined by fan bits A, B, and C, as calculated below:
def get_fan_speeds(capabilities: list[int]):
fan_speed_lut = { 1: 1, 2: 2, 0: 3, 4: 4, 6: 5 }
raw_speed = ((capabilities[0] & 0x10) >> 2) + \
((capabilities[1] & 0x08) >> 2) + \
((capabilities[2] & 0x02) >> 1)
return fan_speed_lut[raw_speed]
The exact mapping as to fan speed names is currently unclear, though the below mapping seems reasonable:
{
1: ["ON"],
2: ["LOW", "HIGH"],
3: ["LOW", "MEDIUM", "HIGH"],
4: ["LOW", "MEDIUM", "HIGH", "VERY_HIGH"]
5: ["VERY_LOW", "LOW", "MEDIUM", "HIGH", "VERY_HIGH"]
}
Note that these values may not correspond with the actual numbers provided to the fan system - verification will need to be done.
Known fan speed values (and model numbers associated with certain fan speed values) are below:
| Fan Speed Value | Model Numbers | Supported Modes |
|---|---|---|
| 3 | SVZ-KP30NA | 0x02 (Low) 0x03 (Medium) 0x05 (High) |
| 5 | MSZ-GS12NA, MSZ-FS06NA | 0x01 (Quiet) 0x02 (Low) 0x03 (Medium) 0x05 (High) 0x06 (Very High) |
Sample Packets
[FC.7B.01.30.10] C9.03.00.20.00.0A.07.05.E4.25.A6.BC.94.B8.A6.B8 2D // SVZ-KP30NA
[FC.7B.01.30.10] C9.03.00.20.00.14.07.75.8C.25.A0.BE.94.BE.A0.BE 09 // MSZ-GS12NA
[FC.7B.01.30.10] C9.03.00.20.00.14.07.75.0C.05.A0.BE.94.BE.A0.BE A9 // MSZ-GL06NA
[FC.7B.01.30.10] C9.03.00.09.04.14.07.75.00.00.00.00.00.00.00.00 DB // MSZ-GE35VA
[FC.7B.01.30.10] C9.03.00.20.00.14.07.75.8C.25.A0.BE.94.BE.A0.BE 09 // MSZ-FS06NA
[FC.7B.01.30.10] C9.03.00.08.04.14.07.75.00.00.00.00.00.00.00.00 DC // MSZ-FD25VA
[FC.7B.01.30.10] C9.03.00.20.00.14.07.F5.8C.25.A0.BE.94.BE.A0.BE 89 // MSZ-LN35VGW