[dmauch]

Here are some pictures of my new 5 axis control box. As shown it has the ethernet Smooth stepper and a G251 for the 5th axis. Power supply is a 600W 12.5A meanwell 48VDC power supply. I recently upgraded my cheap chinese 4/5th axis trunnion table. I removed the A axis 6/1 pulley drive and replaced it with a 30/1 precision worm drive. The C axis was updated with a 10/1 gearhead drive.

Dan Mauch

[Dan73]

hey Dan!
2 questions

1) do you have a diagram of you system, because I have the g540 + smoothstepper + 4 nema23 on it with a 48VDC 600watts too, but I want to add a 4th (5th) axis with the g251 too
2) what kind of rotary you have ? which one you suggest ?

Thanks

[dmauch]

I have wired up my G251 as follows. First off I used a double pole single throw switch so the G540 and the G251 can engage or disengage the outputs. The center two terminals are wired together and to the PS V- . One pole top terminal goes to the G251 disable terminal 11. The other pole bottom terminal go to the G540 Enable terminal 10.
The my 600 W power supply has two wires going to the power terminal for the G251 and two others for the G540. The G251 has the 4 wires that comes from terminals 5,6,7 and 8 for the motors two phases.
For I-set you can either place the correct resistor for the motor current or you can run them out to a db9 connector terminals 1 and 5 if you have your motors power connectors on 9bd a with resistors.
Last I used a 2 pin MTA connector from port 2 of the ESS pins 2 and 3 for the step and direction from the ESS to terminals 10 and 11. I used another 2 pin MTA connector that goes from pin 24 of the ESS port 2 to terminal 12 of the G251 for logic ground.

I took a cheap Chinese 4/5 axis trunnion table and removed the 10/1 ratio pulley drive and added a 10/1 gearhead motor drive for the C axis. For the A axis I removed the A axis timing belt drive and added a 30/1 precision gearhead . If I had to do it over I would have simply made my own.

Dan Mauch

hey Dan!
2 questions

1) do you have a diagram of you system, because I have the g540 + smoothstepper + 4 nema23 on it with a 48VDC 600watts too, but I want to add a 4th (5th) axis with the g251 too
2) what kind of rotary you have ? which one you suggest ?

Thanks

[MegaMoog]

Dan Mauch,
I'm curious as to the positional accuracy of the A & C axis after you modified the trunnion?
Did the backlash improve?
I have the same trunnion n having trouble getting good repeatable positioning! I've messed with steps per rev, made sure belts were tight but it seems that there is still some kind of backlash/slop either mechanically or the motor/drives are not good enough.
Even tried using backlash adj in Mach3...
I level the table with Y axis using an indicator, zero DRO, then MDI +90 deg on "A" axis n use machinist sq to check basic angle. Usually comes up short. Type in -90 deg on "A" axis n comes up even shorter than before. I have tried increasing the steps per rev in motor tuning. Can get a little closer to actual 90 deg.
Just seems as though I don't get the same rotational distance when reversing directions? Was hoping that what your using was giving better results! I know its not professional equipment, but thought it would be a little better than what I'm getting!
I've been pricing some other Harmonic, Worm and Geared type drives just to compare n see if they would be compatible with this trunnion.
Do you have model numbers of your mechanical drives that your using?


Thanks