General Electric IC693CPU372-AE TCP/IP Ethernet Communications Module

In the equipment selection stage of the control system, IC693CPU372-AE considering the advantages and disadvantages of PLC anti-interference performance from various manufacturers, it is necessary to choose products with high anti-interference ability, including electromagnetic compatibility (EMC), especially the ability to resist external interference, such as using floating technology and PLC with good isolation performance. Secondly, it is necessary to understand the anti-interference indicators provided by the manufacturer, such as common mode suppression ratio, differential mode suppression ratio, voltage resistance, and the allowable working environment in which high electric field strength and magnetic field strength are allowed. Another best method is to examine the usage of this type of PLC in similar working environments.

Using high-performance power sources to suppress power grid interference

In IC693CPU372-AE control systems, power plays an extremely important role. The interference from the power grid is mainly coupled into the PLC control system through the power supply of the PLC system (such as CPU power, I/O power, etc.), the power supply of the transmitter, and the power supply of the instrument with direct electrical connection to the PLC system. The power supply for PLC systems generally adopts a power supply with good isolation performance. The power supply for transmitters and instruments directly connected to PLC should choose products with small distributed capacitance and large suppression band (such as using multiple isolation, shielding, and leakage inductance technologies) to reduce interference with the PLC system.

In addition, the IC693CPU372-AE power supply should be separated from the power supply of the entire power supply system, and a shielded isolation transformer is generally added when entering the PLC system. The secondary side of the shielded isolation transformer must be connected to the PLC system using twisted pair cables of no less than 2mm2. The shielding body is generally located between the two coils on the primary and secondary sides and connected to the ground, which can eliminate direct coupling between the coils. In addition, when the power supply harmonics are severe, a filter can be added in front of the isolation transformer to eliminate most of the power supply harmonics. If necessary, a low-pass filter can be connected to the power supply line to filter out high-frequency interference signals. The filter should be placed before the isolation transformer, that is, filtering first and then isolating. Separating the power supply system and using separate isolation transformers to separate the power supply of controllers, I/O channels, and other devices also helps to resist grid interference.