Author Topic: Testing/calibrating a 4-axis stepper motor drive system  (Read 3165 times)

gr8dane

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Testing/calibrating a 4-axis stepper motor drive system
« on: September 28, 2013, 12:16:58 PM »
Hello,

I am a complete newbie. I have ordered a 4-axis drive system without stepper motors. I already have a 3-axis system that was shipped complete, was turn-key and operated perfectly out of the box. Now, I need a 4-axis box. In order to avoid purchasing a complete 4-axis system with 4 new motors (which I don't need) and spending at extra $150 or so, I have purchased a 4-axis system with no motors.

The new system comes with set-up instructions as shown below. I think I just need help with steps 2 and 3. I will purchase a multimeter from HarborFreight as soon as the drive box arrives.

I can send a pic and a schematic of the drive box - if that would help. You can also look at www.xylotex.com, which is where I purchased the system.

Can you help?

Best regards,
Jay

[01] Turn Red Rocker power switch OFF, then Plug in IEC power cord (supplied) to Box and 110VAC power outlet.
 [02] Turn ON Power Supply and measure that the DC voltage does NOT exceed 30VDC (27.5V is a good voltage to use). A red LED and the fan should both power up
 [03] Adjust the Vref at REF's (Black Lead to GND, Red to XRef) Turn Potentiometer counterclockwise for +. Vref = Motor Amp/Phase * 0.8 (i.e. a 2.0A/phase motor X .8 = 1.6V) Never set Vref higher than 2.0V.
 [04] Turn OFF Power Supply, and wait until the supply is fully discharged before proceeding.
 [05] Unplug Green Screw Terminals from drive board.
 [06] Feed motor cabling through grommet hole on back panel. Leave the panel seated in the drive box bottom half to help maintain rigidity of the panel (acrylic).
 [07] Hook up stepper motor cabling to Green Screw Terminals.
 [08] Make sure that the Motor Phase wiring is correct, and that there are no stray wires to cause a short. A mis-wired phase or short can destroy the drive board.
 [09] Double check motor connections.
 [10] Plug in screw terminals
 [11] Turn ON Power.
 [12] The motors should "lock up" (not turn with finger pressure).
 [13] Use PC running program such as Mach3/4 or LinuxCNC to control the box through the PC parallel port and a user supplied parallel port extension cable to the drive box.

SeanB

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Re: Testing/calibrating a 4-axis stepper motor drive system
« Reply #1 on: September 28, 2013, 01:00:55 PM »
If you have bought the motors from the same supplier, and they are the same for both boards, then you just need to adjust the voltage to 2.00 Volts. This will give the right current through the stepper motors.

With the cheap HF multimeter, read the small sheet of paper that comes with it first, then try it to measure a few safe household items. Try a 1.5v cell, like an AA cell, a 9V battery and a 12V remote fob battery for starters, using the  DC voltage ranges on the meter. Then change to the resistance ranges, and see that metal objects are pretty good conductors, well under 1 ohm in most cases, and that things like wood are reasonable insulators, and that the graphite lead in a pencil is an intermediate conductor, draw a thick line on some smooth card and measure the resistance, which will be in the range from 100R to 100k for a short strip, depending if you used a 2B or a 4H pencil to draw them.

To measure the power supply you will need to have it on the 200VDC range, and to measure and set the reference voltage you will have to have it on the 20VDC range.

Just note that those boards do have some built in poor design decisions, and are rather prone to burning out when run for long periods, and there are a few mods to improve reliability, one being adding an external 12V supply for the digital side to reduce the heat dissipated in the voltage regulator on the board.

gr8dane

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Re: Testing/calibrating a 4-axis stepper motor drive system
« Reply #2 on: September 28, 2013, 08:16:06 PM »
Thank you for the very helpful reply. Your information was very useful.

Regards,

Jay