5 Axis CNC using a G540 and G251

[dmauch]

Today I built a 5 axis system for a customer. I used a G540 for 4 axis and then added a G251 for the 5th axis. I ran into a problem where the G540 requires disable line to be connected to and ESTOP 9 or any other) switch that is normally closed to ground for the windings to be energized. On the other hand the G251 requires a nomally open to ground so that the windings are engaged. I had planned to use a SPST switch but obviously that wouldn't work so I installed a DPDT switch which solved the problem. I was sort of surpised that the G540 and the G251 needed different disable configurations but I am sure my customer is going to be happy with his 5 axis system. The above is provided for generally information if you plan to add more axis to your existing G540.

Dan Mauch
www.camtronics-cnc.com
stepper and servo motors.
kits, custom and assmbled cnc systems

[denz]

Hi Dan,
Any chance of some further information.
Break out board, Wiring Diagram.
I am rebuilding my machine to use two motors on the X Axis so i need a 5th driver for the 4th Axis. At the moment I am using a g540.
Any help appreciated.
Cheers
Denis

[dmauch]

I have built so many different variation of the G540 that I don't need a schematic. I have probably built over 400 of them. Here is what I do.
first I added a db25 cut out in the back panel for the second parallel port cable.

I mount a g251 in the bottom of the case. I wire the G251 according to the G251 data sheet with the exception of the disable pin. You will need a dpst switch for use with the enable.disable function. The middle terminal of one side of the switch connects to the G540 terminal 10 and the other side of the switch connects to ground. On the other side of the switch the G251 disable terminal connects to the middle terminal and the opposite of what the g540 wiring connects to to ground. This is really odd. I called marcus at Geckodrive and asked them why the G251 uses a disable function while the G540 uses the enable function.

So the wiring is quite simple but you do need another parallel port.
Dan
Camtronics, inc. -- CNC with Dan Mauch

Dmauch@camtronics-cnc.com

Originally Posted by denz Hi Dan, Any chance of some further information. Break out board, Wiring Diagram. I am rebuilding my machine to use two motors on the X Axis so i need a 5th driver for the 4th Axis. At the moment I am using a g540. Any help appreciated. Cheers Denis

[denz]

Thanks for the reply Dan,
Now i have some idea and something to work with.
All the best to you and yours for Xmas.