What's new
What's new

Fanuc Manual Pulse Generator Wiring Help

M.B. Naegle

Feb 7, 2011
Conroe, TX USA
The MPG pendant on our 2006 Hardinge VMC2000p3 (Fanuc Oi-MC) had a cracked case and the wire jacketing was decomposing. I purchased (what I thought was) a comparable made-in-Taiwan MPG online, as the original MPG was made in Taiwan along with most of the rest of the machine, and went to wire it up today. The electrical schematics that came with the mill seems overly vague, with the only connection diagram showing 4 wires, while the pendant has 12 connections, plus some extra wires for other applications. The pendants come with a pin-out diagram that says which color wire goes to which function(0v, x1, x10, etc. etc.), but none of that is written on the circuit board that the wires plug into. The terminals that the wires connect to have wire numbers beside them and I can't find them in the Fanuc diagrams.

We had replaced the MPG maybe 8 or 9 years ago and still had the paperwork from that one, so I used the old pendant schematic and how it was connected to the board to decipher how the new wires should connect (The prior pendant, the original pendant, and the new one all have different colored wires for everything) and when I went to turn the machine on it blew one of the fuses on the back of the button panel.

I'm assuming I have a wire or two crossed, and I highly doubt the seller's going to have any more technical support than what came with the pendant, so does anyone have a schematic showing how the MPG should connect to this control? Something that says which wires/terminals are for what functions?

The wires connections currently consist of:

Pendant side - Control side
vcc(5-24v) - +5v
oV - 0v
A+ - HA
B+ - HB
A- - (not connected)
B- - (not connected)
X - 28A
Y - 29A
Z - 32A
4 - 324
5 - (not connected)
X1 - 49
X10 - 307
X100 - 308
LED+ - (not connected)
LED- - (not connected)
(braided jacket) - (ground)

Anything stand out as being wrong? The ground wire was loose previously. I remember the LED lamp working years ago, but not sure where it's supposed to connect.
Ok... found one issue.... The new pendant reads "Tosokn" (made in Japan). Other's I'm seeing online are made by "Tosoku," notice the spelling. I think I got ripped off:(.
Any recommendations of where to get parts/support for Hardinge in Houston?

We bought this machine new through Regal back in 2006 and were oblivious that they had off-shored to Taiwan until the machine was on the floor. Had some issues with support from Regal before they went out of business. This is back when our shop was in rural Texas with not a lot of close-by help, so we just assumed supporting the machine on our own and hadn't found a new Hardinge distributor to work with yet after moving to the Houston area.

This mill's made a lot of money for us, but unless those rumors' about Hardinge bringing their manufacturing back to the states are true (where they can keep a better grasp on QC), Doosan's proven to be a better company for us.
I’ve bought 3 or so of those mpg’s off eBay. They are pretty much all the same functions, just different wire colors. The retraction cables are always cracking or getting dropped.
I think your mpg is fine. My suggestion is the take the old one and the new one to an electronics shop and ask them to ohm out the new mpg and label per the old one. It’s quick enough to hook your multimeter to ground and check the pinout.
They may not be confused by the encoder wires, but sometimes they are actually labeled inside the mpg cover.
Not on Fanuc but looked at mine (pokeys made in Taiwan) and the ground is floating per the controller builders mode/plug. Not the 0 volt, the com ground.
We made some progress with this issue. We bought another MPG that was the same make/model as the previous and original MPG's, but the wiring schematic they came with didn't jive with how they were connected to our machine. Essentially the "correct" way to wire it involves a couple wires not being where the MPG schematic said they would be. Hardinge didn't have any other diagrams, but we sorted it out with the help of a local service tech. and found out that we burned out the 'Z' position on the axis selector knob of the new MPG, so until the NEXT new MPG arrives, we wired '4th' axis on the knob as the 'Z' axis, as we don't have the 4th axis on the table currently. We tried using the axis selector's out of one of the old MPG's, but even though they're the same make/model, the inner components are different.

Moral of the story, even if wiring doesn't make sense, if it works, think twice before you try to "correct" it.