I’ve been working through the list of upgrades I want to add to my OMTECH ZF2028-60. Next on the list is adding the 4-pin aircraft connector somewhere accessible inside the cabinet. The existing “Y” axis plug is all the way to the back righthand corner (underneath the anode end of the tube) and (for me) can’t be reached without a great deal of difficulty, so I won’t be manually swapping connectors.
When I added a rotary to my 50W (a much smaller cabinet) I used a 4PDT toggle switch with the output of the driver going to the center contacts, this allowed me to switch between the two 4-pin connectors. Well, after reading this thread Rotary Steps per revolution has changed? - LightBurn Software Questions - LightBurn Software Forum, and specifically @Albroswift’s comment about “not putting any means of disconnect between the driver and motor” it seems that idea is no longer a viable solution.
Also in that thread @ednisley mentions that the KT332N controller has a U axis output, that the manual suggests “could” be used for a rotary. His laser uses it to change bed height, but on my mine the U axis is unused (bed height is controlled by buttons on the front panel). I was hoping to use the U axis (by adding a third driver), but I don’t think Lightburn will let me access it in the rotary setup.
I’ve also considered installing a 3PDT switch on the output of the Y axis from the controller. That would allow me to toggle between the existing driver/stepper motor and a second Y axis driver that would be connected to my rotary. The biggest problem I’ve had is finding the room inside the electronics compartment to add any of this stuff. There is very little room on the back of the electronics bay and no room on the deck. It appears that OMTECH has succeeded in cramming 10lbs of you know what into a 5lb bag. If anyone has any suggestions, I’m all ears.
I will let others comment on the other parts, but I think you should not rule out using a Y-R switch. I so not hot-switch mine, although I was told it does not matter by opinions I trust (read experienced in electronics). You might get into a lot of aggravation trying to go the U-axis route.
I never had any problems with it, I just wish I knew what the issue was that @Albroswift was referring too. It’s possible that the vendor was concerned about noise or interference. I only ever switched it with the power off, never hot. Anyway, I’m going to take your advice and go the Y-R switch route again (I’ve got another switch on order). The next problem is drilling a hole through the two separate sheet metal walls. The back wall of the electronics bay is about 3/4" away from the inner wall of the workspace, with the back wall almost completely covered with stuff that can’t easily be moved.
Only issue I am aware of is disconnecting the stepper motor from the microstep driver while microstep driver is powered, rotating or idle. I was going to do the multi pole switch on my fiber but the microstep driver documentation warned against it. Went a different route.
Had a gentleman posting on LMA burn his out by disconnecting the rotary from the back of the case without powering down couple times.
Easy part to replace, not expensive, but online troubleshooting is a bear if you’re not looking for a bad driver.
I thought the switch was to eliminate unplugging the rotary. If you have a GRBL controller and the $1 setting is under 255, the power to the steppers drops off within 1/4 second. I keep power on then all the time ($1=255), so No Hot Swap for me.
The steppers we use are constantly powered/ green light always on. So even when there is no movement the driver is still sending “Standstill Current” to the motor. The way I understand it, unplugging or throwing the switch same thing.
EDIT Always powered when the power supply is turned on!
Depending on how much, my rotary will move by hand when on but takes some force, I have it set for 1/2 current standstill.
When powered off or “Enable” on the microstep driver is high it turns freely.
Just checked the one with the 4a motor and 6:1 reduction, cannot move by hand when microstep driver is powered even at 1/2 standstill current. The 1:1 will turn by hand when powered, tried it on a rotary table and I could position it without disengaging.
I went with a dedicated driver for my U-Axis, with its own wiring to the inside of the cabinet area. Used an aircraft type connector afixed to the wall inside and easily accessible.
Then I can simply connect the matching male end coming from the rotary’s stepper motor at will. Of course, I power down too just to be safe.
I didn’t want to have to be dealing with different steps/unit between the different stepper motors.
Once setup, I simply change to “Enable Rotary”. Been a little while since using the rotary though but IIRC, I had to also load settings accordingly.
Stepper drivers run around $50 more or less, shielded wiring, switches, etc. cost only a little.
Not having to roll the cabinet around, opening panels, etc. is nice.
Now it’s just lowering the bed down by buttons, set the rotary inside and connect the plugs. There’s the alignment to the interior where the laser rests over the chuck but I’m working on making a platform to aid in quicker setup. Other things going on as usual, but that’s my game plan.
This route is one I’m still considering. I can pick up a driver for about $20 and switch the output of the controller between drivers, instead of switching the output of the driver between connectors. Having a third driver would also give me the option of using the U axis output for rotary "IF" there is ever a version of firmware/software that would support it.
My hands shake so badly that I would never be able to solder the wires onto anything smaller (like the one you used). This one lets me use terminal lugs that I can screw on, still a challenge, but one I can manage.
