ABB 1TGE120021R0010 in the PLC control system, the power supply occupies an extremely important position. Grid interference into the PLC control system mainly through the PLC system power supply (such as CPU power supply, I / O power supply, etc.), transmitter power supply and power supply with the PLC system has a direct electrical connection to the instrumentation power supply coupling into the. Now, for the PLC system power supply, generally use the isolation performance is better power supply, and for the transmitter power supply and the PLC system has a direct electrical connection to the instrument power supply, and has not been paid enough attention to, although a certain amount of isolation measures, but generally not enough, mainly the use of isolation transformer distribution parameters, inhibit the interference ability of the poor, by the power supply coupling into the common-mode interference, differential-mode interference. The main reason is that the use of isolation transformers with large distribution parameters, poor interference suppression ability, coupled by the power supply and into the common mode interference, differential mode interference.

ABB 1TGE120021R0010 for transmitters and common signal instrumentation power supply should be selected distribution capacitance is small, suppression band (such as the use of multiple isolation and shielding and leakage technology) of the distributor to reduce the interference of the PLC system. Bit to ensure that the grid feed point is not interrupted, can be used online uninterruptible power supply (UPS) power supply to improve the safety and reliability of power supply. And UPS also has a strong interference isolation performance, is an ideal power supply for PLC control system.

ABB 1TGE120021R0010 In order to reduce the power cable radiation electromagnetic interference, especially the frequency conversion device feeder cable. I in a project, the use of copper tape armored shielded power cables, thereby reducing the electromagnetic interference produced by the power line, the project went into operation and achieved satisfactory results. Different types of signals are transmitted by different cables, signal cables should be layered according to the type of transmission signal Ovation, it is strictly prohibited to use the same cable with different wires at the same time to transmit power power supply and signals, to avoid signal lines and power cables close to the parallel Ovation, in order to reduce electromagnetic interference.