安装与调试Installation & commissioning

仪表 4-20mA 与 RS485 接线、抗干扰与故障排查Instrument 4-20 mA and RS485 wiring, noise immunity and troubleshooting

读数跳变、无信号、满量程，多数与接线和干扰有关。本文讲清二线制/三线制区别、屏蔽层接地、布线规范与常见故障判断方法。Jumping readings, no signal and full-scale output usually trace back to wiring and interference. This article covers two-wire versus three-wire, shield earthing, wiring practice and fault diagnosis.