HESG447419R1 ABB

In the case of strong interference or high reliability requirements,an isolation transformer with shielding layer should be used to supply power to the PLC system.An LC filter circuit can also be connected in series on the secondary side of the isolation transformer.At the same time,you should also pay attention to the following issues when installing:

(1)It is best to use a twisted pair connection between the isolation transformer and the PLC and I/O power supplies to control series-mode interference;

(2)The power line of the system should be thick enough to reduce the line voltage drop caused by the startup of large-capacity equipment;

(3)When the PLC input circuit uses an external DC power supply,it is best to use a regulated power supply to ensure the correct input signal,otherwise the PLC may receive a wrong signal.

在干扰较强或可靠性要求较高的场合，应该用带屏蔽层的隔离变压器，对PLC系统供电。还可以在隔离变压器二次侧串接LC滤波电路。同时，在安装时还应注意以下问题：

（1）隔离变压器与PLC和I/O电源之间最好采用双绞线连接，以控制串模干扰；

（2）系统的动力线应足够粗，以降低大容量设备起动时引起的线路压降；

（3）PLC输入电路用外接直流电源时，最好采用稳压电源，以保证正确的输入信号，否则可能使PLC接收到错误的信号