Recent years, every programmable controller is promoted and used in a variety of textile machines. Most applications are frequency-changeable and speed-adjustable control systems, which, formed by combining PLCs and transducers, are also used in logic control, production process control and production process parameter control and so on. PLCs are increasingly and widely used in every machine in the textile industry. The traditional PLCs, however, have many short comings such as low level of integration, poor openness, difficulty in operation and so on, which lead to complex wirings due to the redundant IO contacts, high rate of malfunction, difficulty in field maintenance and high maintenance cost. As for the customers who still use the traditional PLCs, the problems like large volume, poor in compatibility, difficult in upgrade have bothered them during the period of their equipment upgrade.