Lightobject.com Support Forum

for some reason when I make long complicated runs, I seem to be losing or gaining a step here and there. it does other things like circles or other things we cut just fine, but it just seems to be losing its place a lot, sometimes just a little, but sometimes a lot. I'm using a gecko drive so I don't have + and - connections for pulse and direction inputs. hooked up the + pulse to pulse and + direction to dir. ground coming out of the board to the common on the gecko. the settings for the board are pwm+dir. I read somewhere in the documentation for the gecko that it calls for +5V to the common, but if I do this I can't seem to get the machine to move correctly. could the gecko being a 10 microstep drive and the motors being full step motors be the issue? I'm kind of new to the linear motion thing, still learning so if that was a stupid question my bad. for some reason I really don't think that's the issue, but I may be wrong and I'm trying to exhaust every option I can think of. I've added heatsinks to the gecko drives in case they were getting too hot, because the problem seems to be getting worse the longer the job goes, thought it may have been overheating, but it still didn't fix it. put in resistors to get the current for the motors within 5% of the rated current. I'm not really sure what else to do.

Hi,
I run Gecko 201's on my setup and don't have any problems with them. Have you tried slowing the cut down a little bit just to see if it makes any difference and the Gecko does need the +5 volt to the common to work properly. Have you gone through the wiring diagram again to see if you have missed something? if your power supply is more than 300mm (1 foot) away from the Geckos then you may need to put in the recommended capacitor on the power inputs of the drive.

4,6 and 8 wire steppers can be run in full, 1/2, 1/8, 1/10 right up to 25,000 steps per rev. It's all handled in the stepper drive. What it does is energise 1 coil a little bit more than the other then for the next pulse it energises the same coil just a little bit more than the opposite one and so on until the full step (1/200 of a rev) is reached. Then the process starts all over again for the next set of pulses for that particular coil set.

5 phase steppers are a different beast as they can be run in only full or 1/2 step but at full step they are 500 pulses per rev and 1/2 step they are 1000 pulses per rev and very smooth. Vexta make this kind as do a few other manufacturers.

There isn't much need to go over 1/10 stepping as the benefits are not worth the extra overheads of a faster computer needed to pass the pulse train to the drives. 8-10 micro stepping is about the best all round performance.
If you go to the Geckodrive.com web site and have a read of Mariss' explanation on steppers and the way they work then you will be armed with a great deal of knowledge on them.

Here is the link, http://www.geckodrive.com/ark-2/support.html