Generally speaking, various components such as servomotors, AC drive, display devices, switches and sensors are used in the equipment. A programmable logic controller (PLC) is used to control such equipment. PLCs are originally designed to replace electromagnetic relays used in conventional automated systems and perform control in a predetermined order. This is called sequence control. On the other hand, in recent years, various machines have been required to have higher performance. Machine controllers were created to control various devices that perform complex movements at high speed using servos and AC drive. In this way, machine controllers and PLCs were created for different purposes, so their specialties are different. While PLCs are good at controlling input and output (I/O), machine controllers are good at controlling complex motion control at high speed and with high accuracy.