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General Mach Discussion / Re: Steppers are too slow
« on: December 01, 2011, 05:23:22 AM »Today I disconnected all drivers from the BOB and connected each one individually one at a time. As I reconnected them, each one still ran slow and the microstep switches still have no effect on speed or torque levels. The motors don't even make a different sound with each selection.IMHO your not going to be able to detect visible or audio changes with different microstep settings. Though technically microstepping does have subtle effects on torque I really doubt you'll be able to see or hear any difference. Maybe between NO microstepping and (say) 10 but other than that I doubt it very much so I'd not get too bogged down in that. As I said - set them as near 10 as you can and leave them there.
Also I went into Mach 3 and changed the kernel speed through the range of 100 hz to 75000 hz with absolutely no effect.To calculate the CORRECT kernel speed multiply your steps per unit by your max velocity (in motor tuning) and divide by 60. Do this for each axis and choose the LARGEST figure. That gives you the max steps per sec you'll ever use. Then pick the LOWEST kernel speed above that figure. Any kernel speed above that is not only pointless but may cause other problems. Post your figures so we can check.
The computer is about 8 years old and is a Pentium 4, 3.2 Ghz processor wit a 2.75 Gb of Ram. I had a fairly new hard drive completely formatted and windows reloaded to be used for this purpose when I first started to set up for this project. the steppers are running off the parallel port on the motherboard but it does have another parallel port PCI card installed. Do you think it is worthwhile trying to use this other parallel port, or maybe removing the card in case it is having any effect on the output pulse rate?I very much doubt this will make any difference.
I do have some doubt about the BOB as I still can't get 2 of the output pins to work on any of the stepper drivers but they will work if connected to the other available pins. My next thought is to replace the breakout board with a different type. Do you have any suggestions?You may or may not have a couple of pins out on either your parallel card or your BOB but if all four of your axis are working on other pins I very much doubt this is the cause of your speed problem.
I appreciate this might not be the best matched system, but the attached You tube URL has the identical components on a friends machine and it can be seen how fast it operates. There is no way these steppers are running this fast.Well if you say it's identical fair enough - but are you absolutely sure?
Exactly the same power supply, drivers, motors, AND GEARING? EXACTLY? The reason I'm checking is if you look at this link (http://www.wantmotor.com/ProductsListB.asp?id=88&Pid=75) the systems APPEAR to be similar to yours but if so, they seem to "randomly" include different power supplies. For example the THREE axis kit has a 24V 350W ps but the FOUR axis system has TWO 36V supplies. It's not clear to me if that's TWO 350W or TWO in parallel give 350W.
IF for example you had TWO 24V 350W supplies you could series them and get 48V at 14.5A which would double the stall speed of your system. (incidentally this is why I say random supplies - 14.5A is waaaaaaaay more than those 4 motors need, so with that supply, the voltage is way too low and the amperage capabilites way higher than neccessary)
Ian
EDIT: didn't see Tweakies post when I posted but FWIW with a supply of 14.5A (if that is indeed what you have) I doubt very much you'll get a voltage drop. Just a thought.