>>>>>1、DEVICEREAD(读出软设备状态值)计算机向PLC发送:
始命令首地址位数终和校验STXCMDGROUPADDRESSBYTES>>>>ETXSUM例子:从D123开始读取4个字节数据
02h30h>>>>>31h,30h,46h,36h30h,34h03h>>>>>37h,34h地址算法:address=address*2+1000h再转换成ASCII31h,30h,46h,36hPLC返回
STX1STDATA2NDDATA.....LASTDATAETXSUM注:最多可以读取64个字节的数据
例子:从指定的存储器单元读到3584这个数据02h33h35h38h34h03h44h,36h
2、DEVICEWRITE(向PLC软设备写入值)始命令首地址位数数据终STXCMDGROUPADDRESSBYTES1STDATA2NDDATA...LASTDATAETX例子:向D123开始的两个存储器中写入1234,ABCD
>>>>>02h31h31h,30h,46h,36h30h,34h33h,34h,31h,32h,43h,44h,41h,42h