When an AC servo drive is switched to “Servant On”, it generates high or low frequency noise during operation and can interfere with peripheral equipment (Ex.: PLC, HMI, etc.) through conduction or radiation, which often results in communication errors or abnormal operations. The following methods can resolve this issue:
- Power separated from the servo drive and controller since the (EMI) generated by the servo generally influences controllers such as Human Machine Interfaces (HMI) and Programmable Logic Controllers (PLC) through the power circuit, it is therefore recommended to separate the power from the servo drive and controllers to reduce the effect (EMI).
- Cable shielding to minimize electromagnetic interference. It is recommended to use shielded twisted pair cable for communications. This will help reduce noise (EMI) in controllers by radiation or conduction.
- Wind the ferrite onto the AC servo drive RST and UVW power connector terminals. When AC servo system is switched to "Servo On", interference (EMI), like common high-frequency signals, appear. The use of ferrite magnet rings effectively reduces high frequency signal interference in power cables, signal cables and connectors so that normal signals can be transmitted.
- Devices properly connected to ground (eg, AC servo drive boards) often experience electrical leaks that interfere with peripheral equipment through metallic objects such as wires and screws. The best way to avoid this problem is to use one ground cable for each AC servo drive and one for each controller to connect to the ground terminal. The reason is that if AC servo motors and controllers are connected by a single ground cable to the ground terminal, electrical leakage will immediately affect other peripheral equipment through the cable and create greater interference; second, the area of the last contact on the ground wire is too small to effectively prevent electrical leaks from interfering with other devices.