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Author Topic: Loosing steps Add a second Y axis DRO for mach3  (Read 397 times)

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Loosing steps Add a second Y axis DRO for mach3
« on: April 22, 2020, 03:11:28 PM »
I am having a bad problem with lost steps, and was wondering if a second DRO display for the Y axis. Am using Y Master and Y slave.
The lost steps are always coming from the Y slave driver to the left side Y stepper motor.
If I switch the cables to the steppers, send the Y slave driver output to the right side stepper, the right side stepper starts loosing steps.

This looks like it points to the driver, and not the stepper motor.

What could be the cause of loosing steps?
The below test was ran Wednesday morning. Tuesday afternoon it was not possible at all to run the same code at 75IPM without it failing and loosing steps.

I was surprised this morning for it to run so well until later in the test, and I realize thet 200 IPM is extreme for me.

Here is some testing I have done at different speeds.
Material 3/16" plywood, 1/8" single flute end mill,  cutting 0.050" per pass, the letter outline I'm cutting is 12"x14"

Test 1 pass 60 IPM
Test 2 pass 60 IPM
Test 3 pass 75 IPM
Test 4 pass 75 IPM
Test 5 pass 100 IPM
Test 6 pass 125 IPM
Test 7 pass 150 IPM
Test 8 pass 175 IPM
Test 9 fail 200 IPM  Realign gantry
Test 10 pass 75 IPM
Test 11 pass 75 IPM
Test 12 fail 75 IPM  Gantry skew left 33" right 34 3/4"
Stepper temperature left 170 F   right 185 F
Mr. Chips
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Re: Loosing steps Add a second Y axis DRO for mach3
« Reply #1 on: April 23, 2020, 01:18:04 AM »
The general unwritten rule for reliable machine operation is to find the maximum Velocity (in Motor Tuning) at which the motor (or motors) start to stall then reduce that figure by at least 25% and save the changes. Repeat for each axis. Then perform a similar operation with Acceleration. (Overall the higher the Acceleration the better but reduce it, if necessary, to stop the machine shaking when performing short movements).

This will reduce the maximum feed-rate available to the Gcode and in your case it will probably be around 150 ipm.
KEEP SAFE !
Re: Loosing steps Add a second Y axis DRO for mach3
« Reply #2 on: April 23, 2020, 09:58:59 AM »
Thanks I understand that, please read the explanation of what I did and how the lost steps changed sides, Sorry guess I didn’t make my problem clear.  If I could have attached a drawing this could have been simplified but I don’t know how to do that.

Originally I ALWAYS lost steps on the LEFT side the Y Slave stepper side of the machine.  The RIGHT side Y MASTER stepper NEVER lost steps.

All the stepper wiring have a 9 pin connector on the side of the control box.

To troubleshoot the problem I unplugged the Y slave stepper connection and the Y master stepper master connector from the side of the control box.

I then connected the Y slave stepper connector to the Y master driver connector, and connected the Y master stepper connector to the Y slave driver connector.

Confused yet?

In summary, the Y slave driver is now controlling the Y master stepper on the right and the Y master Driver is controlling the Y slave Stepper driver on the left.

In this wiring configuration now I ONLY LOOSE STEPS FROM THE RIGHT SIDE OF THE MACHINE,  THE Y MASTER STEPPER that is driven by the Y slave driver.

So, this rules out both a loose stepper connector on either side, and a bad stepper motor on either side because the problem switched sides after switching the Y master and Y slave connectors.

That’s leaves I THINK either the Y Slave driver causing the lost steps or the hardware or software.  This is where the lost steps are coming from that always cause lost steps.

Thanks
Hager



Mr. Chips
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Re: Loosing steps Add a second Y axis DRO for mach3
« Reply #3 on: April 24, 2020, 01:52:51 AM »
Obviously you did not get the answer you wanted to hear  :)

If you have proved that the problem lies with just one axis stepper driver then the best solution would be to replace that driver.

If, for some reason, you cannot do that then reduce your Velocity and Acceleration settings (as mentioned above) to a figure that the problem driver can handle.

Tweakie.
KEEP SAFE !
Re: Loosing steps Add a second Y axis DRO for mach3
« Reply #4 on: April 24, 2020, 02:12:25 AM »
A fellow from CNCZone sent me a couple of videos that I needed because I had been using a XP PC for the past ten years and this one is a Win 10, one of the videos dealt  with optimizing windows and the other grounding.  That was good to do anyway.
I have a new driver in the Y master spot I could move it to the Y slave spot and if the problem switched sides that would indicate that the older driver was the problem. 
Think I will do that and see what happens.
Mr. Chips
Retired 3M'r