SSD:從幀起始定界符;
F_code:數(shù)據(jù)幀類型判斷符,數(shù)據(jù)類型分為:
“過程數(shù)據(jù)幀”:(F=0~4),周期性數(shù)據(jù),其從幀數(shù)據(jù)有16bit,32bit,64bit,128bit或者256bit;
“消息數(shù)據(jù)幀”:(F=12),偶發(fā)性數(shù)據(jù),其從幀數(shù)據(jù)有256bit;
“監(jiān)督數(shù)據(jù)幀”:(F=8,9,13,14,15),其從幀數(shù)據(jù)有16bit;
Addr:地址位;
Data:根據(jù)數(shù)據(jù)幀的不同,數(shù)據(jù)幀有效長度為16bit,32bit,64bit,128bit或者256bit;
CheckSum:校驗(yàn)序列;
ED:分界符結(jié)束。
具體的數(shù)據(jù)序列結(jié)構(gòu)如下圖5所示: