G540 Random fault light on power up

[mchm66]

Hi,
I have a G540 on a 48V switching power supply.
Went through the setup and the steppers go into idle ok.
However, the 540 randomly faults on power up. I have to power off/on to clear the fault light. This is very annoying.

The steppers are a kit from here. I believe its the maximum size you can run from a 540.
link

Any help appreciated.

[Cheeta]

Have you gotten any resolution for that issue? I just ran across the same thing last night. I t seems to do it regularly. If I spin a stepper by hand when i power down, then power up, it will not do that. I tried with NO motors and it does that. I am suspecting the power supply has some noise on it at start up. Going to try a big fat capacitor on the PS tonite.

[mchm66]

I had an issue if I turned one of the motors a little and powered up it would fault on occasion but without the motors connected the fault would appear consistently. I put a 2200uf cap on the output and this alleviated the problem somewhat but did not completely resolve it.

I looked at the power up of the supply on a CRO and it did not appear noisey or any overshoot. The rise time to full output power was about 18ms which should not bother the G540.

I tried an old laptop supply I had hanging around and the G540 didn't have any issues with it at all. Came up every time without fault.

In any case the vendor has kindly offered to replace the power supply in case it may have a fault so an update to this will come shortly.

However when the G540 is working with all 4 motors, value for money and size wise, it is very impressive.

[Cheeta]

That is funny! I tried the same exact things you did. Even the same size cap, scope and laptop supply. I got the same exact results. I took the hi res off on the scope to see if I could find any sub uS spikes...nothing. I also found the when the G540 powers up right after power down and no motion on the motors has occurred, it happens more. If it is up and motors have moved and one is in a "in between " state, then it never happens. You can hear that little jerk when they get holding current. There must be some dependance on motor inductance. I tried a set of very low mH motors and it almost disappeared.

Whatever it is, it must be very short duration in the supply. I contacted Gecko and he said if I move up to a 10,000 uF cap, it should go away. I don't have any that big so I need to order one on my next PO.

I agree, the g540 is a very nice little 4 axis package. Easy install. I use it when my clients want a plasma table. Easy interface to the CandCNC torch control.

BTW, this is the first of 10 G540s i have seen this issue. Glad to know someone is on the same page as me.

[mchm66]

This is actually my second G540. I suspected the first one and had it replaced. We'll see if it's a power supply glitch. If not I may need to try the cap, although at 10000uf and the voltages I am working at is going to make it hard. Shouldn't have to with a switch mode supply.

[dmauch]

I don't think the problem was with tjhe PS . It could be from a couple other things.
1. Bad connection on the disable line or a bad switch
2. A bad connection on the charge pump line
3. A glitch in the PC that is causing the 11 Khz singal to drop out

If you flip the charge pump switch to off and it goes away then its probably number 3. Since you switched to an old PC that probably verifies number 3.

Dan

www.camtronics-cnc
I have the latest G540's in stock with the recent mods to the sense lines and the new trim pot location.

Originally Posted by mchm66 I had an issue if I turned one of the motors a little and powered up it would fault on occasion but without the motors connected the fault would appear consistently. I put a 2200uf cap on the output and this alleviated the problem somewhat but did not completely resolve it. I looked at the power up of the supply on a CRO and it did not appear noisey or any overshoot. The rise time to full output power was about 18ms which should not bother the G540. I tried an old laptop supply I had hanging around and the G540 didn't have any issues with it at all. Came up every time without fault. In any case the vendor has kindly offered to replace the power supply in case it may have a fault so an update to this will come shortly. However when the G540 is working with all 4 motors, value for money and size wise, it is very impressive.

[mchm66]

Originally Posted by dmauch I don't think the problem was with tjhe PS . It could be from a couple other things. 1. Bad connection on the disable line or a bad switch 2. A bad connection on the charge pump line 3. A glitch in the PC that is causing the 11 Khz singal to drop out If you flip the charge pump switch to off and it goes away then its probably number 3. Since you switched to an old PC that probably verifies number 3. Dan www.camtronics-cnc I have the latest G540's in stock with the recent mods to the sense lines and the new trim pot location.

Item 1 - Checked, no bad connections.
Items 2 & 3 - Not relevant as this is during the pre-install checks as detailed in the manuals with the charge pump disabled. And it is something to do with the supply as I used an old laptop supply to check the drive and it did not fault once.