42 Operation Theoryclosed loop control algorithm to make it possible. This increasedthe complexity of motion control and not easy to use for a begin-ner.4.1.2 Pulse Type Motion Control InterfaceThe second interface of motion and motor control is pulses traintype. As a trend of digital world, pulse trains type represent a newconcept to motion control. The counts of pulses show how manysteps of a motor rotates and the frequency of pulses show howfast a motor runs. The time duration of frequency changes repre-sent the acceleration rate of a motor. Because of this interface,users can control a servo or stepper motor more easier than ana-log type for positioning applications. It means that motion andmotor control can be separated more easily by this way.Both of these two interfaces need to take care of gains tunning.For analog type position controller, the control loops are builtinside and users must tune the gain from the controller. For pulsestype position controller, the control loops are built outside on themotor drivers and users must tune the gains on drivers.For more than one axes’ operation, motion control seems moreimportant than motor control. In industial applications, reliable is avery important factor. Motor driver vendors make good perfor-mance products and a motion controller vendors make powerfuland variety motion software. Integrated two products make ourmachine go into perfect.4.1.3 Network Type Motion Control InterfaceRecently, there is a new control interface come into the world.That’s network type motion controller. The command betweenmotor driver and motion controller is not analog or pulses signalany more. It is a network packet which contents position informa-tion and motor information. This type of controller is more reliablebecause of digitized and packetized. Because a motion controllermust be real-time, the nerowrk must have real-time capacityaround a cycle time below 1 mini-second. This means that notcommercial network can do this job. It must have a specific net-work like Mitsubishi SSCNET. The network may have opto-fibertype to increase communication reliability.
