Generally, the ACS880 series drives from ABB, Siemens PLCs, and the CMS computer monitoring system are adopted. The drives use closed – loop vector control, share the rectifier unit, and support energy feedback; alternatively, independent frequency converters can be used, equipped with resistance energy consumption braking. The PLC uses Profibus – DP communication to connect the master station, slave stations, and other external devices. The CMS system monitors all the information of the whole machine in real – time, including data such as the current, voltage, and frequency of the frequency converter, real – time position, limit status, fault records, data statistics, etc.