Protocol stack


Thread Starter

Hector Sifon

hi everybody:
I would like to learn more about Modbus Plus, particularly about the protocol stack. I have downloaded information from but there is no explanation about the protocol stack. The only that I have found is a
graphic of the protocol stack. It shows HDLC level, LLC and MAC. My books about Networks identify MAC and LLC as sublayers of Data link layer an HDLC as data link layer (Computers Networks, Tanenbaum). Has the modbus plus a double data link layer?. Where can I find something about the differents fields of each
frame of LLC, MAC and HDLC.
well I think it would be all.
Thank you !!!
Just so you are aware, Modbus Plus is a proprietary network that is licensed by Schneider Automation (Modicon). The standards are not openly published to the best of my knowledge. People wishing to implement this protocol must pay a licensing fee, etc to Schneider and attend training, etc. I would suggest you contact them directly if you have an interest.