描述
PLC的cpu内有指示程序步存储地址的程序计数器，在程序运行过程中，执行一步该计数器自动加1，程序从起始步（步序号为零）起依次执行到最终步（通常为end指令），然后再返回起始步循环运算。plc每完成一次循环操作所需的时间称为一个扫描周期。不同型号的plc，循环扫描周期在1微秒到几十微秒之间。程序计数器这样的循环操作，这是dcs所没有的。这也是使plc的冗余不如dcs的原因。
NEW Sundstrand-Sauer-Danfoss Hydraulic Pump CPB-1018
Sundstrand-Sauer-Danfoss Hydraulic Pump CPB-1474 A
NEW Sundstrand-Sauer-Danfoss Hydraulic Pump CP180
91 Sundstrand-Sauer-Danfoss Sundstrand Hydraulic Pump
90 Sundstrand-Sauer-Danfoss Sundstrand Hydraulic Pump
89 Sundstrand-Sauer-Danfoss Sundstrand Hydraulic Pump
88 Sundstrand-Sauer-Danfoss Sundstrand Hydraulic Pump
Sundstrand-Sauer-Danfoss Hydraulic Series CPC Pump A59
Sundstrand-Sauer-Danfoss Hydraulic CPC Pump A68
Sundstrand-Sauer-Danfoss Hydraulic Series CPC Pump A58
Sundstrand-Sauer-Danfoss Hydraulic Series CPC Pump A57
Sundstrand-Sauer-Danfoss Hydraulic Series CPC Pump A56
Sundstrand-Sauer-Danfoss Hydraulic Series CPD Pump HP
Sundstrand-Sauer-Danfoss Hydraulic Series CPC Pump A54
