PM864AK01 ABB

In the PLC control system,when the input signal changes,the relevant output signal will change,and there is a certain time delay between them.

Definition:The time required from the change of a certain input signal of the PLC system to the change of the relevant output signal of the system is the I/O response time.

It can be known from the circuit scanning process of the PLC that the external information must be prepared before the I/O scanning stage of the previous scan cycle,and read into the input image area by the PLC.After a scan cycle time in the computer,in this scan The I/O scan phase of the cycle is output to the peripherals,which is the scan time that the system must have.

在PLC控制系统中，当输入信号发生变化时，必将引起有关输出信号的变化，这之间是有一定的时间延迟的。

定义：从PLC系统的某一输入信号变化开始到系统有关输出端信号的改变所需的时间为I/O响应时间。

由PLC的巡回扫描过程可知，外界信息必须在前一个扫描周期的I/O扫描阶段之前准备好，并由PLC读入到输入映象区，在计算机内经历一个扫描周期的时间，在本扫描周期的I/O扫描阶段输出给外设，这是系统必须有的扫描时间。