LG PI-485 protocol
Slovensky
EnglishLG PI-485 protocol
The protocol supports reading and writing data with LG's proprietary serial (2-wire RS-485 bus) PI-485 protocol. This protocol is used by LG air conditioners and heat pumps for communication.
The protocol has been deployed to communicate with the LG Therma V heat pump (HU071MR U44).
Required line parameters:
Communication line category: Serial, SerialOverUDP Device Redundant.
Transfer parameters: baud rate 4800, 8 data bits, 1 stop bit, parity NONE.
Other parameters see the Communication line - configuration dialog box.
Communication protocol: G PI-485
Station address – a number in the range from 0 to 63 (according to the configuration setting of the LG device) specified either as a decimal number or a hexadecimal number with a hash at the beginning (e.g. #1A).
Station protocol parameters
Configuration dialog box - tab „Parameters".
They influence some optional parameters of the protocol.
Table 2
Full name | Meaning | Unit | Default value |
|---|---|---|---|
Retry Count | A retry count of the request in case of a communication failure. | - | 1 |
Retry Timeout | The delay between request retry in case of a communication failure. | ms | 0 milliseconds |
Wait First Timeout | The delay after sending the request before reading the response. | ms | 100 milliseconds |
Wait Timeout | The delay between response readings till its completing. | ms | 100 milliseconds |
Max Wait Retry | Retry count of response reading till its completing. | - | 4 |
Passive Mode | Activating the passive mode. In this mode, no requests are sent, only messages read from the bus are processed. | YES/NO | NO |
For further information on protocol parameters, see the topic Communication line - configuration dialog box.
Possible I/O tag types: Ai, Ao, Ci, Co, Di, Dout, Qi
The address of the I/O tag is textual. The following table shows a list of existing addresses:
Address | I/O tag type | Description |
|---|---|---|
LOCK_REMOTE | Dout | Set the remote controller functionality: Lock (1) / Unlock (0). |
LOCK_REMOTE_RD | Di | Get the remote controller functionality: Lock (1) / Unlock (0). |
OPERATE_OUTPUT | Dout | Set the device functionality: the device is stopped (0) / working (1). |
OPERATE_OUTPUT_RD | Di | Get the device functionality: the device is stopped (0) / working (1). |
OPERATE_DHW | Dout | Set the domestic hot water heating in the built-in boiler: disabled (0) / enabled (1). |
OPERATE_DHW_RD | Di | Get the domestic hot water heating in the built-in boiler: disabled (0) / enabled (1). |
OPERATE_MODE | Ao | Set the mode of operation: 0=cooling, 1=dehumidification, 2=ventilation, 3=auto, 4=heating. |
OPERATE_MODE_RD | Ai | Get the mode of operation: 0=cooling, 1=dehumidification, 2=ventilation, 3=auto, 4=heating. |
TEMP_OUTPUT_SP | Ao | Set the desired outlet water temperature. |
TEMP_OUTPUT_RD | Ai | Get the desired outlet water temperature. |
TEMP_DHW_SP | Ao | Set the desired temperature of the domestic water in the built-in boiler. |
TEMP_DHW_RD | Ai | Get the desired temperature of the domestic water in the built-in boiler. |
TEMP_WATER_IN | Ai | Current inlet water temperature. |
TEMP_WATER_OUT | Ai | Current outlet water temperature. |
TEMP_ROOM | Ai | Current room temperature (external sensor connectable to the indoor heat pump unit). |
TEMP_TANK | Ai | The current temperature of the domestic water in the built-in boiler. |
TEMP_SOLAR | Ai | The current temperature of an optional external solar system (if connected). |
CONNECTED_IDU | Di | The indoor unit is connected (1) or disconnected (0). |
TGT_TEMP_SEL | Di | The current setpoint is the temperature of air TEMP_ROOM (0) or water TEMP_OUTPUT_SP (1). |
Note: Temperatures are integer numbers (°C).
Note: it takes longer to set the values (approx. 12 seconds).
Example: TEMP_OUTPUT_SP has a value of 40 °C. After writing a value of 42, only after approx. 12 seconds does the value of the I/O tag TEMP_OUTPUT_RD change to 42.
February 2008 – Option Checksum.
August 2009 - Support of the value DOUT.
Ver. 1.0 – September 2021 – Protocol implementation
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