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Fanuc 21i PLC modification needed


Oct 18, 2009
Sorry if this is wrong forum, it seems the closest.

Have a DeVlieg 4K-96 (not that it matters, it's just fun!) with a Fanuc 21i-M series A control. We had to change out ancient spindle drive and need separate RUN-FWD and RUN-REV signals for new drive. Although both are on the electrical print and wired to I/O cards, the reverse signal is NOT implemented in the PLC. Argh.

This control seems unable to edit PLC online, but we have ladder file saved to memory card. Is there someone I can hire to duplicate the current spindle-run rung, remove M3 from one and remove M4 from the other? Should be a pretty simple change. There is not a lot to that rung and this machine has run fine for 20 years with this PLC code.

Asked around and it's amazing how many folks respond with a blank stare... lol.

Thank you.
Never mind. After contacting several "machine service" companies, I did it myself. First of all, they pretty much had no idea to do what I wanted (which is crazy!). The owner of the one said they probably couldn't do it even if we knew how, because of "liability concerns". If anyone wonders why most every country in the world is kicking our a$$, maybe therein lies the answer. Get on the web and you will find videos of people all over the world doing whatever it takes to fix things, make a buck, get by. Meanwhile in this country we are so overwhelmed by FEAR that we can no longer do anything. Mind you I'm not advocating for crazy behavior, but adding a REVERSE signal to a PLC program is not risky.

Basically I think 99% of our populace has become useless morons who should stick to golf. My two cents.