PLC的通信已经愈来愈体现它的价值，在PLC与PLC之间的通信，能够通过信息的沟通和数据的共享来保证设备之间的相互协调，已达到互补的效果。PLC之间的数据转换采用RS232接口来传送数据，而RS232接口只能保证10米的传输距离，如果在1000米的距离内我们可以通过RS485来进行通信，更长的距离只能通过MODEL来进行传输。
PLC的数据传送只是将内部的数据传送到对方的一块连续的地址中，我们把它称为一个表，对方的PLC通过读取表中的数据来进行操作。如果表中的数据是一个一般设置的数据的话，那只是一般的数据传送，比如的油价上升了，我要把油价的价格传送到所有的输油机上，那就是数据的共享；而当表中的数据是一段控制PLC的指令程序，那就很有难度了，比如你要控制一台机器人来按你想象的动作工作，你会给它编制一段程序并以数据的形式发送过去。
信息输送的形式有单工位、半双工位和全双工位的分别。单工位的意义也就是说两者之间，一个只能发送，而一个只能接收，比如一个特务他只能接收上司的指示，而无法给上司回复；半双工位也就是两个能都能发送和接受数据，但不能同时发送和接受，比如你打电话时是不能接电话,对方也一样；而全双工位是两者之间都能发送和接受数据，并可同时发送和接受。像互联网就是典型的例子。
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Symbol Technologies LDT ETR 3805-CE0E06E Data Terminal
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Schneider/Modicon 110-090 Cyberline 1000 Servo Drive
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Allen-Bradley 7300-UPW CNC Control Board
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Reliance Electric 45C965 SHARK Output Module
Reliance Electric 45C965 SHARK Output Module
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Honeywell 51305072-400 CLCN I/O Control Board
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MTS Automation FLX Series Servo Amplifer Rack W/PS
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SIEMENS MOORE 15736-64 BDC GATEWAY DATALINK MODULE
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Westinghouse MCP23480R Motor Circuit Breaker
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Allen-Bradley 7300-UPP-2 Processor Interface Board
Allen-Bradley 7300-UAF-2 CNC Control Board
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Nikki Denso Actus Power PFB-10 AC Servo Control Unit
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Control Instruments PRB109 FFA Sentron Alarm Board
Siemens TI 325-07 CPU Module
MTS 400679C Servo Control Board
Nikki Denso Actus Power NPSA-2.5-64 AC Servo Amplifier
Middex-Electronic WK 1T 110V Sensor Controller WK1T
Honeywell 51304584-200 Rev. G EPDGP I/O Control Board
Modicon AS-884A-211 Controller Module
Reliance Electric 0-52840-44A CCC Drive Module
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MTS Automation FLX Series Servo Amplifer Rack W/PS
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Westinghouse NL-325 Numa-Logic Lamp Buffer Driver Board
Westinghouse NL-343 Numa-Logic 4 Input OR Module
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Westinghouse NL-340 Numa-Logic 4 Input Module
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ABB 3HAB2211-1/1 DSQC 256A S3 Robotic Sensor Module
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FANUC A20B-2902-0290/01A Digital Axis Control Module
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FANUC A16B-1200-0150/01A ROM Memory Board
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Honeywell QS7800 A 1001 ControlBus Module QS7800A1001
TRICONEX 2551-1 TERMINATION PANEL
New Monitor Labs ML 81750012 Data Acquistion Board
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New Hitachi BMBM 4Y000066 Control Board
FANUC A20B-2900-0154/05A Control Module
