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PLC is also a computer-based technology and is becoming increasingly sophisticated.Therefore,it can also be used for digital control.

The PLC can receive counting pulses,and the frequency can be as high as several kilohertz to several tens of kilohertz.This pulse can be received in a number of ways,as well as multiplexed.Some PLCs also have the function of pulse output,and the pulse frequency can reach dozens of k.With these two functions,and the PLC has data processing and computing capabilities,if it is equipped with corresponding sensors(such as rotary encoders)or pulse servo devices(such as ring distributors,power amplifiers,and stepper motors),it can completely follow the The principle of NC realizes various controls.

High-end and mid-range PLCs are also developed with NC units,or motion units,which can realize point control.The motion unit can also realize curve interpolation,which can control the curve movement.Therefore,if the PLC is equipped with this kind of unit,the digital quantity control can be carried out completely by the NC method.

PLC也是基于计算机的技术，并日益完善。故它也完全可以用于数字量控制。

PLC可接收计数脉冲，频率可高达几k到几十k赫兹。可用多种方式接收这脉冲，还可多路接收。有的PLC还有脉冲输出功能，脉冲频率也可达几十k。有了这两种功能，加上PLC有数据处理及运算能力，若再配备相应的传感器（如旋转编码器）或脉冲伺服装置（如环形分配器、功放、步进电机），则完全可以依NC的原理实现种种控制。

高、中档的PLC，还开发有NC单元，或运动单元，可实现点位控制。运动单元还可实现曲线插补，可控制曲线运动。所以，若PLC配置了这种单元，则完全可以用NC的办法，进行数字量的控制。