On Sunday 28 February 2010, Cathrine Hribar wrote: >On Sun, 28 Feb 2010 16:23:48 -0500 > > Gene Heskett <gene.hesk...@gmail.com> wrote: >> On Sunday 28 February 2010, Cathrine Hribar wrote: >>>Hi All: >>> >>>I have a problem with my stepper driver board. The board is made by >>>Stepmaster. Board # SOP-1 ver. 1.2 >>> >>>I need steplen, stepspace, dirsetup, and dirhold. >>> >>>Can't get steppers to be reliable faster than Max. Vol. .3 >> >> The first link I found on Google doesn't bode well for making use of the >> device, it will not stand up to the music seems to be the general >> consensus of the postings I read on linuxcnc. The Xylotex boards have >> far better support and are much more convenient to use as they have their >> own B.O.B. >> >> I have 2 myself, abide by the rules and my machine can move 25 ipm with a >> 27.5 volt supply. >> >> They are I believe the same allegro chip used on the xylotex boards, but >> xylotex puts heat sinks on them and recommends plenty of air flow for >> full output. And they Just Work(TM). >> >>>Anyone help? >>> >>>Thanks: >>> >>>Bill >>> >>> >>>------------------------------------------------------------------------- >>>-- --- Download Intel® Parallel Studio Eval >>>Try the new software tools for yourself. Speed compiling, find bugs >>>proactively, and fine-tune applications for parallel performance. >>>See why Intel Parallel Studio got high marks during beta. >>>http://p.sf.net/sfu/intel-sw-dev >>>_______________________________________________ >>>Emc-users mailing list >>>Emc-users@lists.sourceforge.net >>>https://lists.sourceforge.net/lists/listinfo/emc-users > >Hi Gene: > >Thanks for the reply.... > >yes I guess I should have used the Xylotex board, but now I have to work > with what I have within reason. If I do upgrade I will change to servos > as I want to be sure that what I ask my cnc to do it will do it!!! > >I made a index plate for a guy last summer and some of the holes were as > much as .020 off! Can't buy that. > >Bill
Nope, never fly. See if superglueing some heat sinks to them might help, and in my case, I have a pair of old psu fans running on about 18 volts to they really sing to you, one in each end of a box with the xylotex board in it, the box just fitting the outside dimensions of the fans, one blowing in one one end of the box, the other sucking out the other end, so I probably have a 20 mph breeze flowing across both sides of the pcb itself. I've had one fan fail in about 5 years, so if you start with decent computer psu pulls that claim to be ball bearing models, and it lasts 10 minutes at the higher voltage, it should last 5-10 years. I used 18 volts basically because that was the only lower tap I had on the motor psu I built from an old Ampex 2" videotape machine's drum motor power supply. Its a boat anchor if it ever fails... Watch the electrolytic caps, the things in alu cans with plastic wrappers but bare tops. If you see even a hint of bulging of the top of one of those, replace them last week if not before. I haven't read any horror stories about those, yet. But I am a retired C.E.T. and have been seeing problems with those ever since switching power supplies, with their light weight and high efficiencies causing a wholesale shift to their use for nearly everything. Switching power supplies however are _not_ good power supplies for this use, they cannot absorb the energy recycling currents that flow in these chopper stabilized drives without either letting the output voltages soar out of spec, or seeing it as an error and doing a protective shutdown, usually in the middle of the most intricate cut of the job. Been there, done that, built the linear, unregulated but huge output capacitance (75,000 uf, it was handy in my junk box) rig I now use in self defense. It hasn't even gotten warm in 5 years of running 4 motors on my mill, sometimes for several days straight. In any event, I don't think I would, even with heat sinks and fans, push those at above 2.0 amps/motor. That limit will only effect, generally speaking, the amount of force available at slow speeds. Only more voltage can get you above something like 20" a minute, and that will probably need dampers on the motors to achieve that. I'm at about 27.5, so I can go a wee bit faster than the std 24 volt supply will get you to. 30 is pushing the envelope and may let the smoke out of these chips. I run at 2.5 amps, but you could say I have extreme cooling too. For motor dampers, there are several designs extant. Mine are big fender washers with sheet rubber between them in loose stacks, others have used weighted skate wheels and such effectively too. You can see mine, and I'm sure others here will also give links to their designs, on the back ends of the motors you can see in my mess at <http://gene.homelinux.net:85/gene/emc>, that bypasses the front page but only shows you filenames, click to see in most browsers. Or you can take off the 'emc' and see me & the missus and some smaller web sized pix. Good luck. ;) -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Some one needed the powerstrip, so they pulled the switch plug. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
