在现代工业自动化领域，PLC（可编程逻辑控制器）扮演着至关重要的角色。西门子S7-200 Smart系列PLC以其卓越的性能和易用性，成为了许多工程师的首选。本文将详细介绍AIoTedge如何创建一个用于读写西门子S7-200 Smart PLC数据的流程。
一、概述
配置PLC节点参数
Transport: 选择“iso-on-tcp”协议，这是与S7-200 Smart PLC通信的标准协议。
Address: PLC的IP地址，本例中为“192.168.102.23”。
Port: PLC的端口号，本例中为“102”。
Mode: TSAP与Rack/Slot，本例中为“TSAP”。
Local TSAP: 本地传输服务访问点，本例中为“10”和“02”。
Remote TSAP: 远程传输服务访问点，本例中为“03”和“01”。
Connmode: 连接模式，本例中为“tsap”。
Cycletime: 通讯周期，本例中为“2000”毫秒。
Timeout: 超时时间，本例中为“2000”毫秒。
二、读西门子S7-200 Smart
以下JSON流程，可导入你的NodeRED测试。
[{"id":"c8d138cd30e452fc","type":"s7 in","z":"2cc0cdd019e2d62d","endpoint":"374f5d9e3d2741c0","mode":"all","variable":"","diff":false,"name":"读PLC数据","x":220,"y":220,"wires":[["9bb59cb5c92923f1"]]},{"id":"9bb59cb5c92923f1","type":"debug","z":"2cc0cdd019e2d62d","name":"debug 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":400,"y":220,"wires":[]},{"id":"c3f08b05d373b392","type":"comment","z":"2cc0cdd019e2d62d","name":"读取【西门子S7-200_Smart】示例","info":"","x":300,"y":160,"wires":[]},{"id":"374f5d9e3d2741c0","type":"s7 endpoint","transport":"iso-on-tcp","address":"192.168.102.23","port":"102","rack":"0","slot":"2","localtsaphi":"10","localtsaplo":"02","remotetsaphi":"03","remotetsaplo":"01","connmode":"tsap","adapter":"","busaddr":"2","cycletime":"2000","timeout":"2000","name":"PLC","vartable":[{"addr":"I1.2","name":"I1.2"},{"addr":"DB1,INT108","name":"VW108"},{"addr":"DB1,INT200","name":"管道静压"}]}]2-2、连接配置说明
针对【s7 in】，即读西门子PLC，S7系列的节点；需要配置PLC的连接信息，一是IP地址，二是端口。
PS：标记红框处就是需要注意的配置参数，此处配置不正确，导致无法建立连接；该项配置，是针对S7-200；其余型号选择Rack/Slot。
2-3、Node-Red点表配置说明
点位表读取，请参考：https://flows.nodered.org/node/node-red-contrib-s7
PS：V区需要设置成固定的数据块，即DB1；之后可以设定不同的V区地址访问V区变量；例如：要访问 V40.0，请使用 DB1,X40.0；要访问 VW100，请使用 DB1,INT100。
2-4、读取结果
三、写西门子S7-200 Smart
3-1、写S7-200_Smart示例
以下JSON流程，可导入你的NodeRED测试。
[{"id":"c87e89ca50456707","type":"s7 out","z":"2cc0cdd019e2d62d","endpoint":"374f5d9e3d2741c0","variable":"管道静压","name":"DB1.VW200","x":530,"y":480,"wires":[]},{"id":"22d59e0c54565e46","type":"inject","z":"2cc0cdd019e2d62d","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"554","payloadType":"num","x":330,"y":480,"wires":[["c87e89ca50456707"]]},{"id":"374f5d9e3d2741c0","type":"s7 endpoint","transport":"iso-on-tcp","address":"192.168.102.23","port":"102","rack":"0","slot":"2","localtsaphi":"10","localtsaplo":"02","remotetsaphi":"03","remotetsaplo":"01","connmode":"tsap","adapter":"","busaddr":"2","cycletime":"2000","timeout":"2000","name":"PLC","vartable":[{"addr":"I1.2","name":"I1.2"},{"addr":"DB1,INT108","name":"VW108"},{"addr":"DB1,INT200","name":"管道静压"}]}]3-2、写入配置说明
3-3、写入结果
