資料介紹:
ENQ05H請求ACK06HPLC正確響應NAK15HPLC錯誤響應STX02H報文開始ETX03H報文結束幀格式:STXCMDDATA......DATAETXSUM(upper)SUM(lower)例子:STX,CMD,ADDRESS,BYTES,ETX,SUM02H,30H,31H,30H,46H,36H,30H,34H,03H,37H,34HSUM=CMD+......+ETX;30h+31h+30h+46h+36h+30h+34h+03h=74h;累加和過兩位取低兩位命令格式1、DEVICEREAD(讀出軟設備狀態值)計算機向PLC發送:始命令首地址位數終和校驗STXCMDGROUPADDRESSBYTESETXSUM例子:從D123開始讀取4個字節數據02h30h31h,30h,46h,36h30h,34h03h37h,34h