[john1285]

I recently tried to add a fourth axis to my Mach3 system and a problem has developed that is driving me crazy;

This is Mach3 which has been running 3 axis for past few years, everything was good to go, but when I added the new motor same kind as the other 3 wired exactly the same way.

With 4 motors connected to the G540 it will not come out of Fault mode, disconnect the a axis it immediately goes green.

all 4 motors hooked up…. will not come out of fault

All motors hooked up and unhooked while turned off turned off

with any three motors hooked up, tried the new A motor in one of the other connectors… immediately goes green upon start up

tried turning off a axis in ports and pins.. with 4 motors still
connected still in fault

tried switching motors to different connections… same condition

with only 3 motors in any different order.. works fine

as soon a I add the fourth motor in any spot it will not come out of fault

Do I have a G540 problem or a mach3 problem or a computer problem? At this point I am just confused and cannot figure this problem out.

Any help would be appreciated

Jack

[ger21]

It's not a Mach3 problem.

[awerby]

Could it be that your power supply isn't adequate to power 4 motors? If it was me, I'd be on the phone with Geckodrive about this tomorrow, armed with all the specs about the motors, power supply and wiring.

[john-100]

If any 3 of the 4 motors works when connected to any 3 of the G540 outputs
I would suspect a power supply problem

1, what power supply are you using ?

2, how long and what gauge of wires have you used to connect the power supply to the G540 ?

excessive noise or ripple on the supply may be causing the G540 to fault

I know if you switch the power on and off and then on again in quick succession
the G540's fault detector latches up in fault mode and is not reset correctly

John

[john1285]

I think that I got it working by putting a 2 ohm resistor in the DB9 connector of the A axis motor, its the only size I have on hand at the moment, hooked everything back up, turned it on and it immediately went to green. I still have more test to do to see if this a permanent fix but this is the first good news that I have received since I started this project. At least I am able to have all 4 motors connected and turning.

Jack

[Claude Boudreau]

dont know how much current is needed for your motor but according to gecko the value of the resistor between 1 and 5 on the db9 should be amperage X 1000 . Unless you misread the code bar, 2 ohms resistor should give you very low current probably in the milliamps.
but if they are turning so far so good.
It strange because they say you can do without that resistor for 3.5 amp motors.Maybe someone else can tell why this gave you a fault condition...

P.S. it could still be power supply related , if when you had no resistor the motors were drawing too much current ...are you sure the resistor is not 2K?

[john1285]

It was a 2000 Ohm resistor that I put on the fourth motor only that I had on hand. It seems to work, I am a hobbyist an old retired printer at that and electronics is not my long suite
to begin with. The motors said they didn't need a resistor to work with a G540 thats why I choose them and I didn't have any resistors on the original 3 motors this problem didn't show up until I went to four motors.

But hey its working now so I am going to leave it alone for awhile.

Now that its working I going to look for a new reasonable CADCAM product to get and hopefully try to learn.

Jack

[john-100]

Hi Jack

its good to see you have the drive working

the four G250 gecko drives inside the G540 limit the motor current to 3.5A without the resistor

for 3.5A motors its still a good idea to fit a 3K5 ohm resistor so the drive reduces the motor current to 70% when the drives idle
this helps to reduce the motors temperature

the 2K resistor you have fitted has reduced the motor current to 2A

John

[Claude Boudreau]

I agree with John-100 also if the motors dont need the full 3.5 amps put the needed resistor on all motors to reduce current to minimum and make sure you have a fan blowing directly on the back of the G-540 ,by the looks of things, you could be close to either G540 or power supply limits.

Hi Jack

its good to see you have the drive working

the four G250 gecko drives inside the G540 limit the motor current to 3.5A without the resistor

for 3.5A motors its still a good idea to fit a 3K5 ohm resistor so the drive reduces the motor current to 70% when the drives idle
this helps to reduce the motors temperature

the 2K resistor you have fitted has reduced the motor current to 2A

John

[storm2313]

Guys just a quick heads up the G540 doesn't put out 3.5a consistently. That's the drives max amp rating per axis. It delivers 2.47a per axis RMS, or 70.7% of its max which is 3.5a which is real world power consumption as per Marcus.

What it sounds like it could be with the fourth motor is the DB9 connector. Let me explain. Open the connector up and make sure the wires aren't touching any of the contact points, but the ones there meant for. The g540 manual excerpt reflects what could be your issue, and explains why it would be with the single motor. Refer to wiring note number 2.

I would start at the source which an isolated problem, and in your case it's the fourth stepper.

Good luck Jack,
Vince

Attachment 270142

[birdtrick]

I had this exact same problem. No issue with 3 motors but add the 4th and I would get faults at random times. After spending a lot of energy troubleshooting, I finally decided to add the current set resistors to all of the motors. Problem solved. I hadn't done this before because they are 3.5A. The manual says the resistors aren't necessary for 3.5+A motors, but if you have four of them, I would say it is indeed necessary.

I hope this saves somebody else some time.