SLC devicenet

I am having some trouble with devicenet in the SLC processor, and I am now a little confused. first off I keep hearing about this M1 and M0 files which i can address in the plc but i cant look at a data table, and what is this data for. also when i configured the devicenet in the I/O configuration it gave me 32 words of input and 32 words of output.which is suppose to happen What I dont get is how do I know what input or output bit is what. Here is an example of what I am doing. SLC 5/04 1747dnet module, talking to a bulletin 160 drive. I have the inputs mapped in rsnetworx. All I want to do is set a bit for the drive to change. I have looked through some manuals and still cant seem to get an idea of this

Thanks in aDvance
Dallas

Remain calm. Breathe deeply.

If you have only one reference manual, make it the 1747-SDN Installation Instructions.

http://www.ab.com/manuals/io/1747/1747-in058c-en-p.pdf

There is an I/O map in this slim volume that should make the Discrete I/O table (32 words) and the Module I/O table (150 words) clear to you. It also includes a concise reference to I/O Word 0, the Command/Status Word in the Discrete Input and Output tables.

If you post your *.DNT file (zipped for the purpose, of course) I'm sure that all can be explained in even more detail.