A problem with the Z axis is driving me totally mad. I have a 3 axis cnc router and after 5 or 10 minutes of running a program the Z axis stalls when it tries to make a +ve move and just makes a buzzing noise ie no steps. I let it be for half an hour it works and then repeats the problem... I have tried everything (no real help from HEIZ cnc in Germany) and even put a bigger motor on to no avail. It is worse in hot weather??

I have it running through a pci parallel port on my cpu and after checking the pins directly out of the computer port for voltage here is what I get:

X axis pin 2 direction   5v
X axis pin 3 step         5v

Y axis pin 4 direction   5v
Y axis pin 5 step         5v

Z axis pin 6 direction   5v
Z axis pin 7 step         0v ??

I cant understand why I get 0v on step and the motor still goes, is this the problem? pin 1 is spare and is 5v but I am not sure how to swap everything.

Any help would be much appreciated 

It is probably because you have the step low active checked for X and Y axis that you are seeing 5V on these pins. I think your problem is likely to be the drive for the Z Axis. Are the drives for each axis seperate drives? if yes then would be a good idea to swap two drives around and see if the axis problems follow the drive.
Hood

x axis is active low, other 2 arent.

I just swapped the y and z axis drives around in the control box and it doesnt do it anymore? problem shifts.. Could it be wired incorectly in the control box for some reason?

It does have seperately wired drives inside the controller, 2 for the x motors and 1 each for the Z. Funny thing is the x and y are wired the same colours in order but the z is not wired in the same order. I dont want to blow the thing up as this is how it came!!

On output signals in diagnostics enable 1 has a red light on, not sure if this is significant..

 

x axis is active low, other 2 arent.

That is why you see 5v on two but not the other. If you look closely you will see 5V on them when stationary but if you Jog the axis you will actually see it falling slightly. Because it is a pulse and your meter will not be able to keep up you dont actually see the voltage dropping to 0V. Same goes for the other axis, stationary it will be 0v but as you Jog it will go to 5V on each pulse but again your meter will not be able to keep up so you will see just above 0V on it. If you put a scope on these pins you would see what is really happening.

I just swapped the y and z axis drives around in the control box and it doesnt do it anymore? problem shifts.. Could it be wired incorectly in the control box for some reason?

Not really sure what you are meaning. Have you physically moved the wiring from one drive to another? If yes did the problem move from the previously bad axis to another?

It does have seperately wired drives inside the controller, 2 for the x motors and 1 each for the Z. Funny thing is the x and y are wired the same colours in order but the z is not wired in the same order. I dont want to blow the thing up as this is how it came!!

Dont mess with the wiring unless you can work out where each wire is from and where it should go. This is especially true if the axis worked properly before.

On output signals in diagnostics enable 1 has a red light on, not sure if this is significant..

Thats normal


Hood

I took the y drive plug out of the controller and swapped it with the Z plug on the front of the control box and then jogged z using what would normally be the y quick keys. problem didnt occur in z but does now appear in y. I didnt physically shift any wires inside 

 can I tell what definately needs to be where using a voltmeter?



http://www.cnc-router-routers.com/

Controller for S-400, S-720 and S-1000:

Appropriate 1/8 Microstep Controller 4 channel:

4 channel controller
Power up to 2,1A per Phase
4 connections per motor, 1 connection for. 4 end or emergencu switches
connection to PC-parallelport
Microstep controller 1/8 Step
„Sleep-Function“ for energy saving in standby mode
Safety device for high overvoltage points
Power pack
ALU cooling device / 2 ventilators, 80 and 50 .
Option to connect 5 different end or reference switches, and emergency switch
All connections for motors and endswitch -  9 Pol sub D

OK so does the wire you shifted go to the motor? Next thing is to keep the wire shifted and go into config menu, Ports and pins then  motor outputs and swap the pin numbers around for the axis you have changed. Which axis faults now?
Hood

If it works fine for 1/2 hour and then gives you trouble, and the problem is worse when hot weather,
it sounds like something is overheating.  A bigger motor would not help if it is the driver overheating. 
How is the ventilation in the driver box? At least temporarily hook up a fan blowing on the drivers and see if it helps.
Bertho

still having big problems with this  so if anyone has anymore ideas I can try as the machine is pretty worthless as a production item operating like this..

ok heres what I have done since:

*Got a higher rated Z axis motor-didnt fix the problem.
*swapped z and y drives over and still does it.
*contacted manufacturer and they reckon its some software config issue?? any ideas. The standard software is PCNC which is not very good to me so I havnt tried it but they reckon its perfect with that... IM STUMPED

  ooh and I did try taking putting a cooling fan on drivers and no luck!!!

what are you using for a power supply for your motors.  Used together, the motors can take 7.5 amps, and if you are putting bigger ones on, then even more. A power unit to supply 24 volts at 7.5 amps is quite a big ****, and after a while, if it is not up to the job it will give in, or the voltage outpput will fall and cause you steppers to miss.

To try it out  get the machine up and running a test the voltage out of the power supply when running a G0 x1 y1 z1 or something similar that tests all three motors running at once.

this is the controller info belowfor the cnc machine. I dont run a seperate power supply just through the CPU. The problem is always the Z axis and usually happens when it tries to retract upwards at the end of a cut so not necassarily when using all 3 axis at same time. I have 2 controllers  and they are both the same so it cant be a faulty one.



Controller for S-400, S-720 and S-1000:

Appropriate 1/8 Microstep Controller 4 channel:

4 channel controller
Power up to 2,1A per Phase
4 connections per motor, 1 connection for. 4 end or emergencu switches
connection to PC-parallelport
Microstep controller 1/8 Step
„Sleep-Function“ for energy saving in standby mode
Safety device for high overvoltage points
Power pack
ALU cooling device / 2 ventilators, 80 and 50 .
Option to connect 5 different end or reference switches, and emergency switch
All connections for motors and endswitch -  9 Pol sub D.