[Claytonc]

I have an issue where my DRO's will continue but the steppers stop moving randomly. This seems to happen when the machine has been off for some time. I can hear my G540 click or rather the spindle relay kick off when the G540 'trips'. I can turn the power off to the G540 and back on, hit reset and the machine will move again. Sometimes it will work for days after getting past this point of 'tripping' but I want to figure out what is going on... Could this be a voltage problem or maybe there is an issue with my G540?

[CarveOne]

I have an issue where my DRO's will continue but the steppers stop moving randomly. This seems to happen when the machine has been off for some time. I can hear my G540 click or rather the spindle relay kick off when the G540 'trips'. I can turn the power off to the G540 and back on, hit reset and the machine will move again. Sometimes it will work for days after getting past this point of 'tripping' but I want to figure out what is going on... Could this be a voltage problem or maybe there is an issue with my G540?

Is the G540 heatsinked well? Do the motors emit a loud growling sound from stalling? More info and a photo of the G540 mounting method would help.

If the motors don't make a noise and just quit running, then will run again when restarted after a few minutes of cooling off, then the thermal shutdown circuit has tripped. You will need better heatsinking.

Also, do you have the 3.5K ohm resistors in the motor cables or at the G540 motor connectors?

CarveOne

[Claytonc]

I do have the resistors in place. It doesn't seem to be an issue of over heating rather an issue of not being warm enough. If i leave the machine on for a while and run it after an 1/2 hour or so it seems to run just fine. Strange thing. It never does this after it has been on for any length of time, only when its cold.

The motors don't growl at all. Its as if the E-stop has been pressed as far as how the motors sound.

[CarveOne]

Sounds like a really unusual problem. I've not heard of a cold starting problem with the G540 before.

Check the DC output from the power supply and insure that it is starting up in cold temperatures. A regulated switching supply can do this also. Anything that has an oscillator circuit in it can fail to start oscillating at low temps but normally they will start in any temp you can can operate in.

CarveOne

[Claytonc]

The power suply is what I suspected from the start too but I just don't know for sure. I'll stick a volt meter on it this weekend and post back if I figure it out.

[zool]

The power suply is what I suspected from the start too but I just don't know for sure. I'll stick a volt meter on it this weekend and post back if I figure it out.

It might be better to use an oscilloscope to analyze the power supply. It seems there is more to this than just measuring voltage.

[Claytonc]

Sorry, don't have a scope... I didn't get a chance to test it cold today because of having company. Strangly enough it doesn't do it all the time. It didn't do it at all today either.. But it was a warmer day today and its in an unheated (so far) garage.

[zool]

Sorry, don't have a scope... I didn't get a chance to test it cold today because of having company. Strangly enough it doesn't do it all the time. It didn't do it at all today either.. But it was a warmer day today and its in an unheated (so far) garage.

You might try what machine shops do: A warmup program that cycles the X, Y and Z axes for a period of time until the machine and all its components and fluids are warm. This tightens up tolerances, though in your case it would warm everything up so the problems no longer evidence themselves. In MACH 3 there is a Wizard to run the X axis with tool down and a Wizard to run the Y axis with the tool down. You can probably figure out how to program a warm up program from combining these to with Z moves that go almost all the way through the full Z axis movement.

[jsheerin]

Another possibility is that your parallel port doesn't have enough current capability to drive the G540.

[Claytonc]

I like this idea however I don't think it would help in this case because when it happens then the dros just tick away but the machine just sets there... I do generally run the machine's x, y and z axis's to there extremes before starting the first job just to see if its going to fail. The last two days it has started up and ran great. I'm curious to see what it does in a few days when the temp cools down.

You might try what machine shops do: A warmup program that cycles the X, Y and Z axes for a period of time until the machine and all its components and fluids are warm. This tightens up tolerances, though in your case it would warm everything up so the problems no longer evidence themselves. In MACH 3 there is a Wizard to run the X axis with tool down and a Wizard to run the Y axis with the tool down. You can probably figure out how to program a warm up program from combining these to with Z moves that go almost all the way through the full Z axis movement.

[Claytonc]

Another possibility is that your parallel port doesn't have enough current capability to drive the G540.

It seems if it where the parallel cable or card issue that the problem would be more consistant. Still a thought though. My card is putting out 5v.

[jsheerin]

It seems if it where the parallel cable or card issue that the problem would be more consistant. Still a thought though. My card is putting out 5v.

You would think, but no, that's not necessarily the case. Mine ran fine for months only having the problem you describe on one axis very rarely. When I finally put a scope on the parallel port output I was amazed it ever worked at all on any of the axes. The issue is when driving the load of the G540 inputs, the voltage out of the parallel port drops to where it is just barely adequate to make the G540 think it's sent a pulse. But sometimes the level drops slightly more and the G540 thinks it hasn't sent a pulse and thus stops moving. Mine became more consistently bad if I ran my machine at very very slow speeds. I first saw it when I made a diagonal move in x y and z where y was moving 48" while z only moved ~1" in the same time. The z just stopped moving while the dro continued to say it was moving. That's the real trick - figuring out how to make your machine fail consistently so you'll know when you've fixed the problem.

[jsheerin]

You said your card puts out 5V. If it puts out 5V while the G540 is connected, then that's not your problem. But if it puts out 5V while nothing is connected to it, try checking when connected to the G540. The issue I've seen is that the voltage drops under load. On some of the cards I tried, this was different from one pin to the next, so I'd check on the pins you're having trouble with.

[zool]

If its varying voltages that might be plauging you, even when using a PCI add-in parallel port, try one of these or similar:

CNC step SIGNAL BOOSTER for STEPPER MOTOR DRIVERS | eBay

Also, check to make sure the PCI card is firmly seated.

[oldvan]

I'm guessing that your power supply is pushed almost exactly to its limit when all 3 axes are moving simultaneously.

When the machine is cold, grease and oil are thicker, etc. and the steppers take a bit more juice to operate, pushing the power supply beyond its limit.

Length and gauge of wire from the power supply to the G540 could be a factor if too long and too light.

[Claytonc]

I'm sure the voltage of the PS is nearly reaching its limits. I'm also running low voltage LED's from the same PS (Lights dim when in use) but still have the problem even if these LED's are not connected. And I'm not sure about the output voltage on the parallel card when in use. But, It sounds like one or the other or both. I'm about to put a completly different computer together soon. It should have a reliable printer port built into the motherboard and I probably won't have these problems any longer. If I still have issues after the upgrade then it is most certainly the PS. I can adjust my voltage via a pot on the PS but I'm afraid of hurting the gecko G540...

[oldvan]

Ummmm, what voltage are you running the power supply at? (Measured with no load using a digital meter?)

[zool]

A reminder and a suggestion.


On-board parallel ports on the newer motherboards tend to only put out 3.3-volts. A PCI add-on parallel port card will be more dependable than the on-board parallel port; it puts out 4.8-volts [5-volts is theory and round numbers].

I had to read up on the Gecko 540 a couple times before it capabilities and limitations finally sunk in. Some are subtle, so you might, in one sitting, read up on the entire chain of power transmission, both physically and functionally, from the controller software [EMC; MACH3] to the stepper motors. I did these investigations piece-meal and have a flat portion on my head now.

I'm about to put a completly different computer together soon. It should have a reliable printer port built into the motherboard and I probably won't have these problems any longer. If I still have issues after the upgrade then it is most certainly the PS. I can adjust my voltage via a pot on the PS but I'm afraid of hurting the gecko G540...

[Claytonc]

Ummmm, what voltage are you running the power supply at? (Measured with no load using a digital meter?)

For the life of me I can not find my multimeter! Luckly I work in a pawn shop and have several to choose from I'll test it tonight and report back. During setup I believe it was a tad over 24V.

[Claytonc]

A reminder and a suggestion.


On-board parallel ports on the newer motherboards tend to only put out 3.3-volts. A PCI add-on parallel port card will be more dependable than the on-board parallel port; it puts out 4.8-volts [5-volts is theory and round numbers].

I had to read up on the Gecko 540 a couple times before it capabilities and limitations finally sunk in. Some are subtle, so you might, in one sitting, read up on the entire chain of power transmission, both physically and functionally, from the controller software [EMC; MACH3] to the stepper motors. I did these investigations piece-meal and have a flat portion on my head now.

Note taken about the output voltage of the parallel card. I am currrently using an addin card that when originally tested was outputting 5v with no load.

In all your reading about the G540 did you come across the maximum voltage I could safely use?