Help: Weird issue with stepper motors/steps per inch

[gene]

I'm not sure what I've got going wrong exactly

Setup: 2.x laser using retina engrave usb updated to version 4.23 (also use mach3)
Bart's 3-axis laser control board
Stepper motors: both .9 degree and 1.8 degree sets of steppers

Issue: When I first set everything up in mach3 and again in Retina last month, my 1.8 degree steppers were running at 500 steps per inch. I accidentally trashed my trial and error set settings.xml file for the laser while troubleshooting what turned out to be a usb selective suspend issue that was not well documented at all (has to be set to disabled). The steppers would work fine for a good while then jump around and lose zero mid program. I ended up deciding to upgrade the steppers to .9 degree so I could get 1000 steps per inch which is the default for retina.

Fast forward and I've installed the new steppers but am still getting 500 steps/inch on the Y axis. Now however, I'm getting 250 steps/inch on the X axis which is weird. So I swapped out the .9 degree x axis stepper for the old 1.8 degree and am still getting 250 steps/inch.
I dump the retina card and hook back up mach3 (after changing the important 3 axis controller jumpers) - mach 3 is also now saying y is 500/inch and x is 250ish when I do the testing. Before when I originally setup things in mach both axis were 500. So then I mess with the stepper resolution on the controller card. Going from 1/16 to 1/4 to 1/2 does nothing at all to the steps per inch.
I'm pretty much lost at this point and thinking maybe there is an issue with the 3 axis controller or the x axis stepper driver? Any thoughts on troubleshooting this?

[bdring]

If you are really getting 250 step/in with both 1.8 and 0.9 motors, I have no clue what is going on.

Beyond that issue

You need to find out what microstepping you have. I suspect that might be an issue. Check the voltages on the microstepping pins on the drivers to make sure the signal is getting there.

[bdring]

What stepper drivers are you using? I assume Pololu, but what part number?

[gene]

A4983 - bottom of the driver reads Pololu md09b 2011 - I'm testing continuity on the x driver now then testing the MS1, ms2, ms3 inputs to see about the microstepping. Switched the z and the x driver around to see if that makes a difference.

Edit: Ok so i've got both of the .9 degree steppers giving me 250 steps/inch when set to full step resolution. So far so good. Now to get 1000 steps per inch i would then want 1/4 step resolution correct? To get that on the 3 axis board how would i set the pots using the settings listed below? I'm not quite sure how to decode this after looking at again so I think that's my problem. Also you can move this the 2.x laser support section as I meant to post this topic in there originally.

Code: Select all

Encoder Position    Resolution (bit pattern)
0             Full Steps 0,0,0
1             1/2 Step 0,0,1
2             1/4 Step 0,1,0
3             1/8 Step 0,1,1
7             1/16 Step 1,1,1

[bdring]

Please reply with a top view picture of the 3 axis board. I need to see what version it is. I don't have access the the PCB software right now, but a picture will tell me everything I need to know.

[gene]

Here you go

top down view, 3-axis board

[awesomenesser]

Here you go

IMAG0769.jpg

What wire gauge are you using for your AC input? The reason I ask is that it looks like it isn't any bigger the fan wire (20 or 22 awg)? 20 awg can't carry any more than 1.5 amps.

My units uses the following (just checked it with my killawatt):
0.7 A standby
+0.4 A led lighting
+3.4 A laser full power
+1 A air pump
+1.5 A exhaust fan
+? motors (I didn't run them but they should be under an amp)

With everything on that is over 7 Amps at full draw which means I needed at least 14 Awg (probably 12 Awg). Your system might be different but I would be afraid anything under 14awg is a fire risk. (Picture of my setup)

(Here is a chart which tells you the max draw for each gauge: link)

[gene]

I think it's 18 but I'm not home. I'll upgrade it to 12 when I get back tomorrow. I havn't been running anything on the relays at all. water pump, air compressor, fan are all being run directly. The smaller wiring there for the relay stuff was just temporary for basic testing that it is getting power I plan on replacing it when I go to actually use it

[bdring]

The picture was to very to have the pull down resistors on the microstepping signals. It appears they are installed.

I am still assuming this has to do with microstepping. The A4988 is a better driver and has its own pull down resistors, but the board should work with both. I would very the voltages change on the microstepping pins of the drivers change when you change the selector switch.

[gene]

Here are the volt readings for the three stepping pins on the x driver. All three pots were set to the pot setting column. I was getting -1.5mv for the zeros below.

Code: Select all

Pot setting    pin1   pin2   pin3
0                0        0     0
1                4.92v    0     0
2                0       4.92v  0
3                4.92v   4.92v  0
4                0        0     4.92v
5                4.92v    0     4.92v
6                0       4.92v  4.92v
7                4.92    4.92v  4.92v
8                0        0     0
9                4.92v    0     0