PLC 5 commands

Hii

Can anyone plz tell me the usage/relation of packet offset,total tns,size field in PLC5 typed read/write and word range read/write commands??
I want to know what values the field will taken if i wanna read /write 1 or 2 or 3 etc locations



Thanx

Have a look at page 14-6 of the DF1 Protocol command set in the link below; descriptions are for PLC-3 but I think will be useful also for your case.

DF1 Protocol

Hope this helps....

- [font=comic sans ms,sans-serif]fuzzy logic[/font]