描述
大、中型PLC(如西门子的S7-300和S7-400系列)一般采用模块式结构。模块式PLC用搭积木的方式组成系统，它由机架和模块组成(见图2-2)。模块插在模块插座上，后者焊在机架的总线连接板上，有的厂家将机架称为基板。PLC厂家备有不同槽数的机架供用户选用，如果一个机架容纳不下所选用的模块，可以增设一个或数个扩展机架，各机架之间用I/O扩展电缆相连，有的PLC需要通过接口模块来连接各机架。
Ziatech ZT8906 Pentium CPU Board w/PCI Expansion STD 32
FANUC A16B-1211-0041/06A MAIN CPU BOARD A16B12110041
HP/Agilent E4406-60060 CPU board Assembly
Hirata Main CPU Board PCA HPC-363D1 HPC363D1 Ref
ADVANTAGE ELECTRONICS 3025 CPU BOARD REV. A
Expedited shipping available
Centigram 2410-0152-02 CPU Board, by AMDEV
AMDEV Communications, 21 Years in Voicemail 1989-2010
Abekas Dveous CPU Board for ACCOM 5100 System
Centigram 2410-0188-01 AIP 120 CPU Board, by AMDEV
AMDEV Communications, 21 Years in Voicemail 1989-2010
SVG Station CPU Board 80166F2-01
SVG Station CPU Board 80266BE-01
