Earthing at PLC/DCS panels serves two critical and distinct roles : safety protection and signal integrity . Improper earthing can cause controller malfunctions, card failures, or even software corruption. Dual Roles of PLC/DCS Panel Earthing Type Purpose What It Protects Panel Earthing (Safety Earth/Power Earth) Provides safe path for fault/leakage current Personnel safety, prevents electric shock, fire protection Instrument Earthing (Electronic Earth/Signal Earth) Provides clean, noise-free ground reference PLC/DCS I/O modules, sensors, 4–20 mA signals, communication 1. Safety Earthing (Panel/Power Earth) Protects human operators from electric shock if panel body becomes energized Safely diverts fault current during insulation failure or short circuit Prevents fire risk from leakage current buildup Connects: Metallic panel body, frame, door, and internal ground busbar to earth pit 2. Instrument Earthing (Signal/Electronic Earth) Provides stable reference ...