ABB GDB021BE01 HIEE300766R0001 Module Controller

Description

The grounding wire of the PLC control system includes system grounding, shielding grounding, AC grounding, and protection grounding. The interference of the chaotic grounding system on the PLC system is mainly due to the uneven distribution of potential at various grounding points, and the existence of ground potential differences between different grounding points, causing ground loop current and affecting the normal operation of the system. For example, the cable shielding layer must be grounded at one point. If both ends A and B of the cable shielding layer are grounded, there is a ground potential difference, and there is current flowing through the shielding layer.

When abnormal conditions such as lightning strikes occur, the ground wire current will be greater. In addition, the shielding layer, grounding wire, and ground may form a closed loop. Under the action of a changing magnetic field, induced current will appear inside the shielding layer, which interferes with the signal circuit through the coupling between the shielding layer and the core wire. If the system grounding and other grounding processes are chaotic, the generated ground current may generate unequal potential distribution on the ground wire, affecting the normal operation of the logic and analog circuits in the PLC. The logic voltage interference tolerance of PLC operation is low, and the distribution interference of logic ground potential can easily affect the logic operation and data storage of PLC, causing data confusion, program runaway or crash. The distribution of simulated ground potential will lead to a decrease in measurement accuracy, causing serious distortion and misoperation of signal measurement and control.

Safe grounding or power grounding refers to grounding the grounding terminal of the power cord and the cabinet body as a safe grounding. If the power supply leaks or the cabinet is live, it can be safely grounded and led underground without causing harm to people.

The system grounding PLC controller is grounded to the same potential as the controlled equipment, which is called system grounding. The grounding resistance value should not exceed 4 Ω. Generally, it is necessary to connect the PLC equipment system ground and the negative terminal of the switch power supply in the control cabinet together as the control system ground. The general requirement for signal and shielding grounding is that the signal line must have a unique reference ground. When shielded cables encounter situations that may cause conductive interference, they must also be grounded locally or in the control room to prevent the formation of a “ground loop”. When the signal source is grounded, the shielding layer should be grounded on the signal side; When not grounded, it should be grounded on the PLC side; When there is a joint in the middle of the signal line, the shielding layer should be firmly connected and insulated, and it is necessary to avoid multiple grounding points; When connecting shielded twisted pairs of signals from multiple measurement points to a multi-core twisted pair shielded cable, each shielding layer should be well connected to each other and insulated, and an appropriate grounding point single point contact should be selected.

Model recommendation:
57160001-UNG
57160001-UNL
57160001-UY
57160001-UZ
57160001-VG
57160001-YX
57160001-ZB
57160001-ZL
57170001-A
5730030-A
5730030-F
5730030-UN
5730030-UP
5730030-UR
57160001-E
57160001-EU
57160001-FH
57160001-FX
57160001-GF
57160001-GR
57160001-GV