So I've finally got my motors running smoothly on the Mach 3 but I've hit yet another problem.

Every so often the motors will stall for no apparent reason. I first thought the lead screws where getting jammed but I've even tried the motors without any load and they still stall.

When the motors stall even if I try to help it to move forward it won't. But the moment I release the jog key and start jogging again it works fine.

Jog at slower speeds causes it to stall less but it does stall. Also when jogging at slow speeds I can hear the motor sometimes hesitate.

See the video or a fast and slow jogging X axis without it being connected.

http://www.youtube.com/v/e1wQHubSqFY

P.S> I don't know what's the BBCode to embed YouTube Videos in this forum.

Anyone with any help? I'm really getting desperate to get this machine going.

It seems like you might have your velocity in mach3 set too high. try turning it down and see if that helps. Also, what is your kernel speed set to, and what are you using for motor drivers and power supply?
-Adam

If I jog at 35% too the motor stalls. Kernel is set at the lowest 25K, PSU is a 40V 10A with the motors driver in parallel and drivers are the Motion Control Products MSD542.

What are the signs of the PSU not being able to take the load of a motor? Or if a driver is reaching peak which is lower than what the motor is demanding?

Another question. Dose this happen on all axis' or just the X? As for the power supply, when you are overloading it it will get hotter quicker, and the voltage will drop due to saturation of the transformer. What are the motors you are using? Are these bipolar or unipolar drivers? I looked at the page about them, but it says its a chopper driver which I thought was only unipolar, but then goes on to mention bipolar also. -Adam

Happens on all Axis, what is also strange is that sometimes when I jog two axis together they will stall together too.

I'm using the following motors
http://www.motioncontrolproducts.co.uk/pdf/FL57STH76-2808B.pdf
and following drivers
http://www.motioncontrolproducts.com/download131.html

I have the same problem with my stepper motor. But it stalled only when I set the velocity too high. Its ok when set to 60IPM. Faster than that and it stalls. I am getting a 48V 10.5A PSU to see if I can rapid faster without stalling. But looking at the speed of the revolution. Its really fast. That will be too fast for the X1 table. I think to rapid at 100IPM on an X1 or X2 would be more than sufficient. The speed you set may be higher than that.

But I could be wrong. I am trying to get about 100IPM with my new PSU without stalling. If that happens, I am very happy.

Alex

OK, a few more questions before I give you an answer. What are the steps per unit you have set in Mach 3? Also what do you have the drive set to for micro stepping?

On another note. I believe you said before that the motors were wired for bipolar parallel. Looking at the spec sheet, the motors have an inductance of 1.6 mH. Using the formula [optimal drive voltage = (sqrt(mH))*32) gives 40.47 volts. You might want to keep an eye on the motors to make sure they are not getting too hot. They will be running at the top of their range.

-Adam

I've used the 2 micro step setting on the Driver. The motors are running absolutely cool no problem there.

My Mach3 is set to MM units and at 1000 step per mm for the x and y axis at Velocity 600mm/min and acc of 200

As mentioned, slow or fast job results in the same thing except at slow jog it stalls less often than at fast jog.

When you jog multiple axis' dose it do it more often? If you try jogging all 3 dose it do it real quick?

What it sounds like to me is that the computer is having of trouble outputting the pulses. If the computer was telling the motor to turn one direction and the direction pin flickered this could cause the stalling. It would try to change directions so fast that the motor would lose it and go into a stall.

What is the computer that mach3 is running on? -Adam

its a Dell Latitude laptop D800, that has been freshly rebuilt as a Standard PC and the Driver Test shows a nice clean line. Its 1.7GHZ and got 2GB RAM.

What are you using for a breakout board? -Adam

Its a standard passive BOB but I am using a USB power to the drivers being driven Active Low.

If I lower the Velocity I get no stalling but if you listen carefully every 10 secs or so you will notice a slight motor hesitation noise.

http://www.youtube.com/v/XmsZw6C_dm0

its a Dell Latitude laptop D800, that has been freshly rebuilt as a Standard PC and the Driver Test shows a nice clean line. Its 1.7GHZ and got 2GB RAM.

If you have access to a desktop computer, try it with that. I was having all kinds of problem running my Taig from a D800 but it works fine from my desktop.

The only problem I'm really facing now is this hesitation once about every 8-9 seconds. At slower velocity the motors do not stall. I've even disconnected the Direction Pulse to see if that helps but nothing helps. I don't have access to a Desktop machine and so am keen to get this laptop working.

Hi Bruce,

Now that you mentioned the hesitation, I had somewhat similar problem with my motor. They will tick every 2 seconds. It happened suddenly with my Asus laptop. It never did before. I was advised here to switch to desktop pc. When I did that, the problem disappeared.

According to people here and Mach3 support, laptops are notorious for wreaking havoc on cnc mills. I suggest you get a real cheap pc (even a PIII with 512MB ram will do as I am currently using) and use that instead of your laptop.

I thought I could safely use my laptop. Now I am resigned to the fact that laptop aren't a good choice for cnc mill.

Alex

So if you run the driver test in the mach 3 folder what are the results? -Adam

Its a nice clean line with an occasional spike

no more suggestions?

I wonder if there's software on the laptop that's doing something every 8-10 seconds, and that's what's causing the hesitation. E.g. virus scanner, wireless network scanning, RSS reader.
Hard to pin that sort of stuff down tho.

D.

I was following you on the mach yahoo group also and I agree with the other guy. It must be the laptop checking the battery status or something. You could try removing the battery and run only off wall power. That might work. -Adam

You guys are not going to believe this. I managed to get the machine working. Now wait for the fun part.

1. Its a HP nc4400 laptop.
2. It doesn't have a parallel port on it.
3. I'm using a docking station.
4. I've loaded Windows XP on it.
5. I've not made ANY changes to the set-up, its still working on ACPI mode.
6. All services and start-ups are running etc.
7. Not loaded the RM Clock utility
8. Not done any optimization at all.

AND IT STILL WORKS FINE. Motors are running smoothly and faster than the machine can handle and there is no hesitation at all.

Sod's law that I got my SmoothStepper today too. Infact I rebuilt this laptop to use with the SmoothStepper and previously I'd tried this same laptop with all the 'recommended' changes and my motors didn't even move!

The only difference is that I'm now using the Development version of Mach3 instead of the lock-down version because that is what SmoothStepper needs.

I'll try this set-up for a few days and if things work then I may have a Brand New SmoothStepper for sale in the UK :-)

Hey bruce miranda,

Sorry to jump in here but i have a similar set up to you from motion control with same drivers and have just finished hooking up all the electronics. They are not connected to the mill yet but i was just wondering what driver switch settings and mach 3 settings that you ended up with after all your problems?

Im just looking for some base settings to go with as i am quiet worried this point in time as i have a nasty high piched squeal coming from my motors when idle, they seem to drive in right direction and at a good speed but this noise does not sound good!

Any advice from your findings would be good as i dont want to hurt things!

Cheers

Darryll

I have my motors connected in parallel so all the current switches are kept OFF to supply full current. I went for a 10 microstep configuration and that means putting DIP 6 and 7 ON and everything else OFF.

There should be no squeal on idle, check that you have a full 5V coming from the parallel port else go for the USB powered Active LOW configuration because the MSD542 is already opto isolated but needs a good voltage to drive them. Most of my problems were due to the fact that the laptop parallel port was 3.3V.

In the end the wiring diagram from Motion was correct as well although it was opposite to what others have used here.

Because I have the Metric X1 the tuning values for X and Y were 1000 and Z was 1333.33 (with 10 microsteps).

Ah thanks very much, i did wonder about the wiring diagram and it has made me think but thats better knowing someone else has used it!

When you say Full 5v from parallel port do you mean check voltage on pins that i am using with a multimeter then? Although its a desktop pc with only Mach 3 on it That could be the issue, process of elimination i suppose!

I am cnc'n a X2 but need to get the mechanical side of things ordered up next, will get the electronic side of things squeaky first!

Thanks for your advice.

Darryll

Use the tools from http://www.beyondlogic.org/pardebug/pdebug.htm and enable a pin and then measure the voltage of your parallel port output on your PC. It should be as close to 5V as possible.

I believe squealing motors may also be because your PSU or driver is limiting the current being supplied to the motors. So something to check.