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Messages - g21

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General Mach Discussion / Re: Am I loosing Steps, and what should I do
« on: January 04, 2017, 03:58:12 AM »
Any update here? Been quite a long time now.

Curious if you figured it out.


General Mach Discussion / Re: Am I loosing Steps, and what should I do
« on: August 11, 2016, 09:36:20 AM »
Hello RussH,

Your drivers are fine with this voltage, they are rated from 18 - 80VAC or 24V - 110VDC. Your mains voltage is a little higher then usual so your driver voltage is also a little higher but well within specs for your drivers. Pulses on the scope look fine, no worries about the ringing at the beginning of the pulse.

Try to reduce the current through the motors by changing the dip switch settings I posted earlier. Try with SW1: OFF, SW2: OFF and SW3: ON. This should reduce your current to 3.7A and peak current 4.45A.

Keep your acceleration low to start with and see what happens. If this works fine, increase your acceleration and speed back to the normal settings step by step until you feel OK with it.


General Mach Discussion / Re: Am I loosing Steps, and what should I do
« on: August 01, 2016, 07:56:01 AM »
Hello KevinRSA

You are correct, I not realize this was a differential input although I downloaded his driver manual. My mistake, let's see what RussH finds out.

Lowering the current is a quick and easy thing to try I think. Checking if the ballnuts are not loose in his machine is also quite easy.

Thanks for straightening this out and correcting my mistake.


The ballscrew should not continue to rotate after your head crashed and stopped. Are you sure the screw kept on turning or did you just look at the screen at Mach 3? Mach 3 will continue to run and the DRO's think the machine is still moving although the actual motor is stopped, blocked or whatever. With the head locked or blocked, the ball screw cannot turn much, maybe a few degrees due to the screw bending and the nut pressing the balls into one side of the grove.

Secondly, the signal you show on the pulse + pin does not make sense to me, did you hook up the scope correctly? Pulse + to scope A in and scope ground to pulse -. you should see a nice square wave and not what you see right now.

If you want to verify the motor turning with the head blocked, why don't you purposely block the head by moving it down to the (scrap) workpiece and see if you can slowly lower it more by jogging the Z down slowly! and watch if the motor is actually turning with the screw turning also? Since you already crashed it and saw something funny, this would confirm it. I think the couplers would slip or the motor would stall out but the screw wont turn more then a few degrees.



You have a good point here, since we don't know anything about the motors the current settings could be wrong. In Russh current set-up according to the pictures posted earlier, the motor current is set to the maximum of 6A per motor and 7.2A peak. I attached a little screen-shot of the dip switch settings per the manual for his drivers.

Definitely worth trying to reduce the current and see what happens.

If all the signals to the drivers are correct and clean and power supply is good, the driver / motor has to be the problem as Russh already rules out mechanical problems if I am correct.

Give it a try and see what happens.



The step input are the Pulse - and the Pulse +, Dir - and Dir + are the direction inputs which seem to work fine and the ENA - / ENA + are the driver enable signals which also seem to work since you can move your axis around.

Since you are gaining steps, the driver must think there are additional pulses coming from the Pulse inputs to be able to make steps. If there is noise or just a bad Pulse signal coming from your card, this could be the reason for irregular and uncontrolled steps. If the signals look nice and clean, stable without much fluctuation then I start to worry about your USB card in the machine. There are quite a few machines out there by now that use the same configuration as yours and run without problem so there must be something wrong with your hardware from the moment you got yours or the computer / USB cable to control the machine maybe the culprit.

Step by step and we will figure this out.



Since you have a scope, could you hook it up to the step input pulse on one of your stepper drivers? Just select a federate of lets say 1000 and see how the pulses look going into your step driver. Connect the scope to the pulse - and pulse + input on your driver. Take some pictures how the signal looks like, it should be a nice stable square wave. since you are having problems on all 3 axis, it does not matter which axis you select, would be good to check all 3 axis and show us how the pulses look like.


Hello Rush,

What design error are you talking about? So far we have not yet determined if there is a design error or not.

A filter on the secondary AC power supply (after the transformer) could help reducing spikes and ripple on the AC. You have not answered my earlier question: what is the AC voltage on your drives? You need a multimeter set to AC and measure the power supply lines for your drives with the machine staic and with the machine running.

If you have access to a scope, you could see what how the power supply for the drivers looks like. Also the power supply for the USB card might need to be checked, this appears to have its own power supply on board so a clean AC input is desired although it appears the card has some capacitors on board. Checking this power supply might help also, a scope will tell you if you have a 'dirty' power supply or not.

Ground wiring is quite simple, every component needs to be grounded once and to one common point. Where this common point is or which part of the machine this is (could be the entire frame) is not important but there can only be one connection from the drives to this point. Since the drives do not have a separate ground wire, I assume the frame, or the metal enclosure I see in the picture is the ground and there is one wire from the metal frame to the yellow/green ground wire. All seems to be correct but is worth checking for lose or bad connections.

Shielded wires should have a ground connection only on one side of the wire, quite simple.

I would start with measuring the power supply lines to the drives and the USB card first. See what the AC voltage is and if you have a scope, see if they are clean.

The spindle drive is connected directly to the AC lines at 220V? (measure the voltage to be sure) If so, I would disconnect the spindle drive from the power supply lines and run the test again, this eliminates the spindle driver and spindle motor from the problem.

Let us know what you find.

This machine has no jibs, is all linear slides. would not hurt to check though but as OP mentioned, it happens on al axis.

Do you have access to a spare USB board in the machine to try? Tried different USB cable (shielded)?

What accel / decal settings do you have set now when this happens?

This does not look bad at all. I would start by untangling the wires for the steppers from the USB card, it looks like they are on top of the card. Secondly I would unplug the green connector blocks from the stepper drives and check for lose or bad connectors.

Also check the connectors on top of the USB card for lose wiring.

I would measure the voltage to the stepper drives, should be close to 70VAC but not higher then 80VAC. Measure for some time and see if it spikes up over 80VAC. Your stepper drives are Leadshine drives after I Googled the partnumber in the picture and these are good drives but don't like overvoltage.

Do you have access to another computer to run Mach3 on? Just to see if this makes a difference.

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