Introduction: The pulse that delivers through control will dominate servo electric machinery dominate PLC, deliver pulse with physical kind, the transistor output that uses PLC namely is the most commonly used means, it is low end commonly PLC uses this kind of means. Before answering this question, want to understand the use of servo electric machinery above all, to common electric machinery, servo electric machinery basically is used at exact location, the control servo that accordingly everybody says normally, it is the positional control of pair of servo electric machinery actually. Actually, servo electric machinery still uses pattern of additionally two kinds of jobs, that is speed control and torsion control, application is less nevertheless just. Speed control is to have transducer implementation commonly, make speed control with servo electric machinery, it is to be used at be being added quickly commonly decelerate or it is circumstance of career choice accurate pilot, because opposite at transducer, servo electric machinery can be achieved inside a few millimeter thousands of turn, because servo is of closed circuit, rate is very stable. Torsion control basically is the output torsion that dominates servo electric machinery, because the response of servo electric machinery is fast,be likewise. Application is controlled with on two kinds, can regard servo driver as transducer, it is to use imitate to measure control commonly. The application with servo the mainest electric machinery or fixed position are controlled, positional control has two physical quantity to need to control, that is speed and position, say exactly, control servo electric machinery where to arrive at with much rapidder rate namely, accurate stop. Servo driver controls the distance that servo electric machinery runs and rate through reception pulse frequency and amount. For instance, electric machinery of our agreement servo every 10000 pulse turn circuit. If PLC delivers 10000 pulse inside a minute, so servo electric machinery walks along circuit with the speed of 1r/min, if 10000 pulse are delivered inside a second, so servo electric machinery walks along circuit with the speed of 60r/min. So, the pulse that delivers through control will dominate servo electric machinery dominate PLC, deliver pulse with physical kind, the transistor output that uses PLC namely is the most commonly used means, it is low end commonly PLC uses this kind of means. And in high-end PLC is the kind that carries news report a number pulse and frequency transfer servo drive, for instance Profibus-DP CANopen, MECHATROlink-II, etherCAT is waited a moment. The channel that these two kinds of means just realize is different, essence is same, to our process designing, also be same. This namely I want to say with everybody, want to learn a principle, comprehend by analogy, is not to learn and learn. Write to the program, this difference is very big, day department PLC is the means that uses a statement, and Europe department PLC is the form that uses functional piece. But essence is same, want to control servo to take an absolutely fixed position for instance, we control the output passageway of PLC with respect to need, pulse number, pulse frequency, increase slowdown time, and need knows when servo driver locates finish, whether to come up against spacing to wait a moment. No matter which are planted PLC, no more than is parameter of the control to these a few physical quantity and motion read take, just differ PLC implementation method is different. CNC Milling