中文
含义
信号错误/异常信号。系统接收到不符合协议定义的错误信号或噪声干扰数据，通讯数据校验失败或识别到非法指令码。
常见原因
- 通讯线路受到强电磁干扰（如附近有变频器或大功率电机）
- 通讯电路上的信号匹配电阻或滤波电容损坏
- 室内机或室外机通讯光耦响应速度下降
- 连接线中的零线和通讯线平行敷设过长
- 系统接地不良，地线回路引入噪声
自助排查
- 检查通讯线是否与电源线分开走线（避免平行捆扎）
- 确认空调系统接地可靠，测量地线对零线电压是否小于5V
- 检查通讯线的屏蔽层（如有）是否单端接地
- 若环境中有干扰源，尝试关闭附近其他大功率设备观察故障是否消除
English
Meaning
Error signal / abnormal signal. The system has received a signal that does not conform to the communication protocol — data checksum failure or an illegal command code has been recognized.
Common Causes
- Strong electromagnetic interference on the communication line (nearby VFD or high-power motor)
- Damaged signal termination resistor or filter capacitor on the communication circuit
- Slowed response from the communication optocoupler on the indoor or outdoor board (aging)
- Long parallel runs of neutral wire and communication wire
- Poor system grounding introducing ground loop noise
Self-Check Steps
- Check that the communication wire is routed separately from power cables (avoid parallel bundling)
- Verify the AC system has a reliable ground — measure voltage between ground and neutral (should be below 5V)
- Check whether the communication cable shield (if present) is single-point grounded
- If nearby interference sources exist, try turning off other high-power equipment to see if the fault clears