- Need Help!- Red "fault" light is lighting on my G540.
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Member
Red "fault" light is lighting on my G540.
It has worked until today when I coupled a rotary drive stepper to it. I have tried to remove the A-axis wire from the drive, but it´s still the same. I can reset Mach3, but when I push the buttons, only the numbers on the screen are running but not the steppers.
What may be wrong?
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Member
Re: Red "fault" light is lighting on my G540.
I removed all the wires, but the red light was there yet. I have also removed the paralell port cable, but still the same. Can it be that the power supply is damaged and doesn´t deliver enough current?
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Member
Re: Red "fault" light is lighting on my G540.
with the parallel printer cable disconnected you will need to switch the charge pump to off ( switch to the right of the printed logo on the G540)
what powersupply are you using ?
with no motors connected what is the voltage you measure at the power supply terminals ?
John
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Re: Red "fault" light is lighting on my G540.
The charge pump has always been off. The voltage is 44V and when I took a quick on/off measurement of the current, it meassured 12A, so it should be more than enough. If I open the black box, can I then find out more? Will it be possible to remove some of the drives from the others in order to find the reason?
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Member
Re: Red "fault" light is lighting on my G540.
44V is OK (it is within the 18 to 50V limits )
with no motors connected you should not see 12A going into the G540 even taking into account current waveform will cause an inexpensive multimeters reading to be inaccurate
with the cover off you will be able to unplug the main board from the four drivers and test the board on its own
you will see each G250 driver is fastened to the base with 2 screws -
note the G250 FET transistors and voltage regulator is only insulated by the black anodised coating, be carefull you don't damage the coating
assuming the main board tested OK
remove 3 drivers plug the main board onto the remaining driver
if that works add another driver and retest
repeat until you find the faulty driver (or all 4 axis are working)
john
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Member
Re: Red "fault" light is lighting on my G540.
I didn´t measure the input current to the drives, but the short cut current of the power supply. I have now removed the drive for the A-axis and the green light came back, so I think something must have been wrong with the rotary stepper motor or maybe the wiring. Are there any ways to troubleshoot that case?
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Member
Re: Red "fault" light is lighting on my G540.
have you have used the rotary axis stepper motor before ?
I expect either the cable has been crushed so 2 wires shorted
or you have a wire break that could be intermittent with just the insulation holding the broken ends of the wire together
with the power on ,
the back EMF generated when a motor coil is disconnected is high enough to destroy the stepper driver H bridge transistors
while you can have a wire break any where
the odds are greater where the wires exits the 9 way plug or enter the motor
with a basic multimeter its not always easy to see the increased resistance of a dry joint
when the resistance of the cable and motor winding is a few ohms and can be comparable to the contact resistance of the meter probes
several times at work
I have had inconclusive resistance measurements while checking multicore camera or audio cables
cutting the last inch or two ( 25 to 50mm) off each end and soldering the connectors back on solved the problem
John
Last edited by john-100; 02-10-2019 at 07:43 AM.
Reason: add ref to multicore cables
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Member
Re: Red "fault" light is lighting on my G540.
I used this motor several years ago, but with another driver and I have resoldered the wire to the gecko plug after that, so maybe I have done something wrong there. The wire has also a middle plug connection near the motor which has been disconnected these years, so maybe some of the pins in this plug have been covered with an oxidation.
Can I test the motor and the wiring with a stable dc current in any ways?
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Member
Re: Red "fault" light is lighting on my G540.
Motor label: KL23H251-24-8B When I tested the wires there was a difference between the coils. I could light a led with one of the coils but not with the other, and I have tested the wires close to the motor, so I believe it must be a damage inside the motor. There was also resistance difference.
I have another new larger motor: 57BYGH78-401B 1.8 degr. 2.8A 1.8 N.m. Do you think I can use that with the Gecko driver? And do you know where I can buy a new driver for best price?
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Edit:
I used the 8 wire motor in serial connection with the red/yellow and black/orange wires shorted and after cutting of these wires, the motor runs more smoothly and I got a light on the led at that coil that didn´t light before. When I short the red/yellow wires, the same problem occurs, so I found that the motor is wired with wrong colours compared to the specification at http://www.kelinginc.net/KL23H51-24-8B.pdf
I have found that the red/yellow and green/blue are connected to each of the coils and my problem is now to find out which of them are a+ and a- ...
Last edited by jaru-eri; 02-10-2019 at 09:14 PM.
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Re: Red "fault" light is lighting on my G540.
That´s how it was connected, but when I connected the red and yellow wires together, it made a shortcut to one of the coils because these wires are the end wires of that coil on my motor. So I assume that my motor is wired with faulty colors compared to the wiring diagram which may have been caused by poor workmanship at the factory.
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Edit:
I have tested the wires again and found that the two coils with red, blue, yellow and green wires all interacts with two other wires, so there must be a shortcut between the coils inside the motor which means that the motor is damaged. So I have to give it a try with the other larger sized motor.
Last edited by jaru-eri; 02-11-2019 at 02:37 PM.
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Member
Re: Red "fault" light is lighting on my G540.
After changing to a new motor and new driver, I got the motor to run but with a very strange sound (like fast ticking). When I tried to tune the pot on the driver in order to fix it, it looks like something went wrong and the force to the motor died and both the green and red leds are lighting on the G540 box. I pulled out the wire to the motor, but the red light is still on. The 3 other motors works normally.
Last edited by jaru-eri; 02-14-2019 at 05:51 PM.
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Member
Re: Red "fault" light is lighting on my G540.
going by the circuit diagram for an early version of the G540 that I found in an old post on cnczone
G540 SCHEMATIC.pdf
I don't see how 3 axis can work with the RED led on
as the enable signal to the G250 driver boards is used to switch between the red & green LED
what happends if you remove the faulty G250 driver ?
I guess its possible is pulling the enable signal down so there is a voltage across the red LED as well as the green LED
are you sure the motor was connected correctly ?
I would email or call Geckodrive.com
John
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Member
Re: Red "fault" light is lighting on my G540.
I´m not sure but do you think it will be possible to get a motor to run in both directions if it´s wrong connected? I will try to remove the driver later and see what happens then.
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Member
Re: Red "fault" light is lighting on my G540.
some times when a stepper motor is wired incorrectly
at first glance it will look like its working
you would hope the motor conforms to a standard colour coding of the wires
assuming the new motor is another 8 wire motor like the KL23H51-24-8B
KL23H51-24-8B.pdf
then you could have odd results if you either mix the pairs of coils
for example connecting the red/blue coil to the brown/black coil and
yellow/green coil to the orange /white coil
wiring two coils in anti-phase
for example connecting blue and yellow together and red & green to the driver
would have dramatically reduced the inductance to less than the minimum 1mH
resulting in an over current
John
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Member
Re: Red "fault" light is lighting on my G540.
The new 57BYGH78-401B stepper motor was a 4 wired bipolar motor. I connected it wrong by connecting the -a to +a and visa versa, and did the same with the b wires, so I didn´t get the motor to run before I changed the settings in the Mach software. Is it possible to overload the drivers that way? Could I have done something wrong in the settings? The motor is rated with a current at 2.8A, so I mounted a 2.7 kohm resistance to the plug pins.
I have now connected a new driver and now only the green led is on, but I´m afraid to try again with the same motor before I know what it was that failed.
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Member
Re: Red "fault" light is lighting on my G540.
swapping A+ with A- and vise versa and / or B+ with B- and vise versa is not going to damage the driver
just change the direction the motor turns if you swap one pair of wires
a 2K7 resistor is close enough as it will set the motor current to 2.7A
the problem is if you connect A+ to B+ and A- to A- for example
if you get the mach3 settings wrong your not going to damage the driver but its possible to step too fast and stall the motor
so far I have not found the 57BYGH78-401B data
with a multimeter set to ohms you should be able to test the motor to find the two pairs of wires
John
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Member
Re: Red "fault" light is lighting on my G540.
I didn´t connect a to b, but I´ve found that maybe one of the wires had a loose connection. Could that be a possible reason?
- Need Help!- Red "fault" light is lighting on my G540.
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