SM920 HollySys Power Module Controller, Shanghai Sijian Intelligent Technology Co., Ltd. is engaged in technology development, technical consultation, technology transfer in the fields of intelligent technology, information technology, and automation technology, as well as the sales of electrical equipment, automation equipment, electronic products, communication products, and electromechanical products. Industrial automation products: PLC, DCS, sensors, frequency converters, encoders, relays, servo drives, soft starters, touch screens. Brands involved in the products include: Eurotherm, Schneider, Siemens, ABB, SICK, P+F, E+H, Yokogawa, Yamakawa, Mitsubishi, Emerson, Honeywell, FANUC, GE, Eaton Electrical, CT
The logic voltage interference tolerance of PLC operation is relatively low, and the distribution interference of the logic ground potential can easily affect the logic operation and data storage of the PLC, causing data confusion, program runaway, or system crashes. The distribution of analog ground potential will lead to a decrease in measurement accuracy, causing severe distortion and malfunction in signal measurement and control. SM920 HollySys Power Module Controller
1. Safety ground or power ground     Connect the ground terminal of the power cord and the cabinet to the ground as a safety ground. If there is a power leakage or the cabinet becomes live, it can be directed underground through the safety ground, preventing harm to people.
2. System ground     The PLC controller is grounded to maintain the same potential as the controlled equipment, which is called system grounding. The grounding resistance value must not exceed 4Ω. Generally, the system ground of the PLC equipment and the negative terminal of the switching power supply in the control cabinet should be connected together as the control system ground.
3. Signal and ground     Generally, signal lines must have a reference ground. In situations where conductive interference may occur, cables should also be grounded locally or in the control room to prevent the formation of "ground loops." When the signal source is grounded, the shield should be grounded on the signal side; when not grounded, it should be grounded on the PLC side; when there are joints in the signal line, the shield should be firmly connected and insulated, avoiding multiple grounding points at all costs; when multiple twisted-pair signal lines are connected to a multi-core twisted overall cable, each should be interconnected, insulated, and a suitable single-point grounding location should be selected.
Compared to soft starters, controller burnout is the most severe failure. For some manufacturers, the return rate due to such failures has exceeded 30%. Such issues are less common in imported or joint venture manufacturers. The main parts prone to burnout are the controller's power supply, trigger circuit, and input circuit.
4. Soft starter malfunction:
It occasionally happens that a motor in operation stops due to interference in the soft starter, or starts due to interference when in a stopped state. The former is more common, while the latter has only occurred with two brands. The reasons are, first, product quality issues, and second, related to circuit layout. However, imported or joint venture soft starters do not exhibit the above phenomena, whereas domestic brands have more such problems.
5. Poor contact of internal connectors in soft starters:
The selection of internal connectors in soft starters should not be an issue, but it is a problem easily overlooked by domestic manufacturers, often leading to failures. Imported or joint venture manufacturers do not make such mistakes. Third, improving machine efficiency