National PC PL40M

I am currently attempting to retrofit a new PLC into a newly purchased Italian made machine. The machine currently has a National PC PL40M plc with two expander units and no software, pc connect cable, or manuals. I do have one printed copy of what I hope is the current program in the PLC currently (All Italian Abbreviated Comments). I am nearly finished copying the program into the new PLC software however one input has me stumped. X179 (Labeled: RIV-!) is listed in the printed program twice however the first expansion unit only has 24 inputs labeled (X100-X124.)The second unit inputs appear not to be used but I assume the labeling would be the same (X instead of Y) as the outputs that are used are labeled (Y200-Y224). Any help in communicating with the plc, insight into X179, or help understanding the Italian abbreviation RIV-! would be most appresiated.

Not much help but a little info I found on Google and this website. It was originally made by MATSUSHITA ELECTRIC WORKS, LTD now Panasonic Electric Works. My best guess about the X179 address is those older plcs allowed addressing well beyond the physical addresses available to allow for expansion units, etc. FPWIN-Pro might program it, I have no way of knowing. Try searching with Google and translate some of the foreign site hits.

Thank you for the responce. I have downloaded FPWIN-Pro (demo) already. This software does not list any ML series PLC in the supported PLCs however looking at this software I was previously able to determine several of the commands function in the hard copy program. No clues however as to what my mystery input X179 is referencing. I have visited every google, yahoo, bing, ect website I could find that makes reference to National PC, PL40M, Matsushita, ect (foriegn translated, and .com.). When you say that it is refencing an address beyond the physical addressing of the expansion unit, do you think that the address may be in error in the program and thus just doesn't turn on or do mean something else.

Additional info:
Machine made in 1990 I assume the PLC is of the same age

Still guessing about the X179. Maybe it is a special relay type device (like a flasher bit or similiar). If you could scan and paste the rungs where it is used maybe we or someone can figure it out. Yes it is possible the original programmer decided to just save the rung with a placeholder (dummy) address for the future.