Thread Content
Grounding installation and maintenance precautions: When grounding instruments, it is essential to follow the relevant grounding specifications strictly; otherwise, it will affect the proper operation of the instruments. The following points should be considered regarding instrument grounding: 1. The power ground of the I/O cabinet and the power ground of the UPS must be connected to the same ground point to ensure equal potential ； 2. The grounding cable must meet the manufacturer’s requirements and be connected to the dedicated grounding screw inside the cabinet ； 3. The system grounding and shielding grounding must not converge at the cabinet; they must be connected to the grounding grid separately ； 4. The cabinet grounding cannot be replaced by cabinet bonding bolts; it must be connected strictly using grounding wires ； 5. The grounding must be firm and reliable, and the busbar connection plates should be coated with anti-corrosion paint ； 6. The ground resistance must meet the requirements of the control system, and it should be measured accurately ； 7. Grounding must be carried out in strict accordance with the manufacturer’s requirements; shortcuts should not be taken to save effort, nor should the specifications regarding the gauge of the grounding wires be ignored ； 8. The AC power supply for the control system should come from a separate system, isolated from other devices and uses ； 9. The power supply should be designed to account for the impact of initial current, and should be able to withstand at least 10 cycles ； 10. The AC grounding of the control system should be connected to an isolation transformer or UPS, or located in its vicinity ； 11. The AC power supply for the control system workstation should use a dedicated socket ； 12. When connecting several I/O interface adapters to the power supply of field devices, isolation barriers should be used ； 13. The AC power supply for the control system should be provided by an isolation transformer or UPS ； 14. When AC and DC inputs are connected to the same terminal block, the terminal block must be marked with appropriate warning labels ； 15. The AC ground wire should be of the same rating as or one size larger than the current-carrying wire ； 16. Reserve an additional wire or use a terminal box to provide a test point ； 17. The resistance of the grounding system must be tested to ensure that it meets the requirements of the control system manufacturer ； 18. The ground wire must be completely separated and insulated from any other wires, and it may only be connected to the actual grounding point of the building ； 19. The diameter of the ground wire shall be at least 3.5 mm ； 20. The ground wire is not the power neutral wire, and it must be separated from the neutral wire ； 21. The grounding impedance measured between the neutral wire and the ground wire of the power socket shall not be greater than 2 ohms (reference value) ； 22. The voltage between the neutral wire and the ground wire, as measured at the power outlet, shall not exceed 1.0 V; moreover, regardless of whether the device is turned on or off, the variation in voltage shall not exceed 1.0 V ； 23. Iron pipes cannot be used as a substitute for grounding wires ； 24. The grounding resistance measured at the grounding terminal of the ground wire shall not be greater than 1 ohm ； 25. Is the ground wire broken, damaged, or severely corroded? ； 26. Is the connection between the ground wire and the main grounding conductor secure? ； 27. Has the soil in contact with the ground become loose due to external forces? ； 28. Check whether the repeated grounding wires, grounding electrodes, and connections are intact and undamaged.