Build Thread- Restoring a Fanuc 21i for testing and a possible retrofit

[Odin M Yggdrasi]

Hi again. I have a Fanuc control that looks like it is missing a few parts, though the mainboard is there and identified out as a Fanuc 21i.

Does anyone have a parts list for what this control needs to operate in terms of just making the control power on and identify itself and it's capability? At the moment it is in a free-standing cabinet not attached to a machine at all, and I am just interested in making it power on so I can determine if it would be a suitable retrofit control for another Bostomatic 312 that the original NC control burned up on.

I know I will be needing servo and spindle drives if I do attempt to connect this control to the Bostomatic 312, and probably new encoders because Fanuc appears to use non-standard ones.

But regarding parts internal to the control- I did find a marking indicating that it needs 24V 8A. Does that sound right to anyone familiar with working on these, and is that the main power input? Or am I missing a power supply module that it should have.

It would be nice if GE would just put their manuals online like Fagor did, but no such luck at the moment and the original books for this are long gone.

[Al_The_Man]

If it is a 21i it can't be that old?
You are most likely going to need servo motors and spindle motor as well as drives, so it may not be a viable proposition.
Also if the power components are missing, then it might pay to part it out on ebay.
If you need a hardware manual, send me a PM.
Al.

[Odin M Yggdrasi]

It isn't that old, though the only date I could find on it was when it's parameters were last backed up before it got removed from service, and that was in 2005.

They don't make suitable hardware to couple this unit to a machine's original servos so that I only have to replace the axis drive login and the encoders?

It does bug me actually that GE almost presents these as something that only they are to know about and work on, if it really is that propietary then it isn't worth my time because it won't work with anything else in the shop.

[Al_The_Man]

Fanuc have always been proprietary based equipment, there were some earlier versions that allowed analogue control of drives, in this case, you could use existing motors AND drives.
There is quite extensive documentation required to integrate one of these systems.
Unless you have the whole package, I would not consider is a practical cost effective project.
Al.

[Odin M Yggdrasi]

That's what it sounds like. I was hoping to be able to re-use as much as the existing control as possible because in the five minutes that the original control ran before burning up everything on this machine worked well. If I could get a control that still would produce analog outputs, I would locate the point in the system where the original NC sends the analog outputs to the drives, cut the wires there, and attach the new control.

Probably I should just look into getting another Fagor control to use, since I already know how to set those up and I know the 8025 with PLC64 will do what I need when set up right.