DCS systems usually use several controllers (process stations) to control numerous control points in a production process, and each controller is connected through a network and can exchange data. The operation adopts a computer operation station, which is connected to the controller through a network to collect production data and convey operation instructions. Structurally, DCS includes process level, operation level, and management level. The process level is mainly composed of process control stations, I/O units, and field instruments, and is the main implementation part of system control functions. The operation level includes: operator station and engineer station, completing system operation and configuration.
When grounding the DCS control system on site, it is necessary to strictly follow the grounding specifications of the DCS manufacturer, otherwise it will affect the reliability of the DCS system. When grounding the DCS system on-site, attention should be paid to the following points:
(1) The power ground of the I/O cabinet and the UPS power ground must be connected to the same ground to ensure equipotential.
(2) The grounding cable must meet the requirements of the DCS manufacturer and be connected to the dedicated grounding screw inside the cabinet.
(3) The system grounding and shielding grounding cannot be combined in the cabinet and must be separately connected to the grounding grid.
(4) Cabinet grounding cannot be replaced by cabinet parallel bolts, and must be strictly connected with grounding wires.
(5) The grounding should be firm and reliable, and the busbar connection plate should be coated with anti-corrosion paint.
(6) The grounding resistance meets the requirements of the DCS system and must be strictly measured.