定时器时间常数的外部输入及应用

External Input & Application of Time Constant of Timer

在PLC中,定时器的时间常数通常由PLC内部产生。PLC输入点的ON-OFF状态可看作是数字量的“0”和“1”,而将不同的输入点及其对应的ON-OFF状态组合起来可形成不同的数据。将该数据作为定时器的时间常数,可实现定时器时间常数的外部输入。以主机是日本OMROM公司的小型机C28P-CDR-AE的TVT-90可编程控制器学习机为例,通过对简易模拟交通信号灯的控制,实现定时器时间常数的外部输入,并实现定时器时间常数的在线更改。

In PLC, the time constant of timer is usuaUy produced inside PLC. If the ON-OFF state of the input point is regarded as the digital quantity ＂0＂ and ＂1＂, and fit for different input points together with the corresponding ON-OFF states, then different ＂0＂ and ＂1 ＂ combinations will be formed and consequently different data will be generated. Taking the data as the time constant of timer, its external input can be realized. This paper takes the case of TVT-90 Programmable Controller machine, whose mainframe is the minitype C28P-CDR - AE of Japanese OMROM Company. With the control of simple simulated traffic lights, both the external input of the time constant of timer and the online time change of the time constant of timer are realized.