Mike, for us non-electrically inclined folks, would you be so kind as to break down how the differences on paper may transfer to real world performance differences for Mechmate application?

Outside of those using smooth steppers, most of us are running at a Max Pulse Frequency of 25K or 45K to the B.O.B. from the parallel port. Unless the extra over head will make the lower end of the spectrum run smoother, 333 kHz upper limit doesn't seem to be of any benefit for Mechmate builders.

Also what does "High-Level pulse" mean and what is the relationship between a lower number and real world benefits?

I'm running O.M. 7.2 geared motors with Gecko G203Vs and the combination of the motor and driver is about $400 per axis. If the combination of the URI Robot with a -say Motion King motor with belt drive can bring the cost of building a Mechmate down without a significant performance hit, this could be a perfect cost saver option for those on a tighter budget. $100 per axis is something that anyone looking into building a Mechmate would be interested in.

It could also mean having enough left over to get that all important CAM package or vacuum hold down. I'm on the cusp of beginning my second build and have been holding off until I can find an alternative to the OM/Gecko combo.

David, you are correct that the 333 kHz limit is way over the specifications needed for driving from a parallel port. I think Mike was just answering a question from earlier.

When you send a step pulse, you need to go from zero volts to ~5 volts, then you need to go back to zero volts in order to prepare to send the next step pulse. "High level" means the time period that the signal is at the higher voltage level. If it's too short, the driver doesn't see it. So the driver has a minimum time requirement.

Since this Gecko spec says 2uS, and 333 kHz, we can see that the "low level" time would be have to be about 1uS in this case - a total of 3uS to make a complete low to high to low pulse, 333,000 times per second. There is no real world benefit to excess capability here, as you have observed. There is a real world detriment if a driver fell short of what you planned to send it (25k to 45k at approximately an 11uS to 20uS high level pulse time). However, that doesn't appear to be the case with anything we are discussing.

Now, I admit to some amusement over the apples-to-oranges comparisons going on in these UI Robot driver discussions. The price comparisons that should be going on are:

A) BOB at $81 to $164 + (4) UIRobot 24004B at $48 each providing up to 4A at 40 VDC. (160W)
B) BOB at $81 to $164 + (4) Gecko G251 at $69 each providing up to 3.5A at 50 VDC. (175W)
C) (1) Gecko G540 at $299 providing the 4 drivers up to 3.5A at 50 VDC. (175W)

Or else:

D) BOB at $81 to $164 + (4) Gecko G203Vs at $147 each providing up to 7A at 80 VDC (560W)
E) BOB at $81 to $164 + (4) Gecko G201 at $114 each providing up to 7A at 80 VDC (560W)
F) BOB at $81 to $164 + (4) UIRobot 24008B at $90 each providing up to 8A at 40 VDC (320W)

The UIRobot drives are actually priced pretty much directly in line with the Gecko drives by power handling capability (*); it's a question of which drive's sweet spot your particular configuration lands in.

So depending on the costs of actually getting the drives to your location, it appears that the UIRobot solutions might save you a few tens of dollars overall. They don't save hundreds.

(*) The 203V adds in a lot more abuse protection for more $$, but that's arguably only important while you're sorting out how to wire things correctly.

...and as Brad already knows, the G540 is an excellent performer with very little needed to integrate into a machine.

Just saying I love the all-in-one device. It's the only version of a MM I haven't done yet! :p

Single axis stepper motor driver VS multi-axis stepper motor controller
 

http://www.cam-mobi.com/UIM-stepper-...and-drives.jpg
Miniature stepper motor controller & stepper motor driver

http://www.cam-mobi.com/install.jpg
Integrated stepper motor driver

http://www.cam-mobi.com/programmable...controller.jpg
Programmable stepper motor controller

http://www.cam-mobi.com/24204-steppe...r-with-can.jpg
Intelligent stepper motor controller

http://www.cam-mobi.com/intelligent-...n-protocol.jpg
Multi-axis stepper motor controller

Shanghai Expo
Stage lighting design by stepping motors.

Integrated Stepper Motor with Drives
 

UIROBOT is the leading supplier of integrated stepper motor from China.
NEMA17 integrated stepper motor with holding torque 0.44N.m and 0.65N.m
NEMA23 integrated stepper motor with holding torque 1N.m and 2N.m
NEMA34 integrated stepper motor with holding torque 3.5N.m and 8.5N.m
http://en.uirobot.com/upload/archive...1274149404.jpg

Version 2 UIM240 Parallel Port Stepper Driver have been on sale
And Version 2 UIM241 and UIM242 stepper controllers with encoder or sensor terminals for cloosed-loop motion control by stepper motor and S curve Accel and Deccel function is coming to market this Sept.:)

For the African / South African market... I have just received a batch of UIM 24004 drivers....like the ones that I run on my machine. Price R 695.00 each plus postage.

For the African Market...I now have the UIM24002 (2Amp) stepper drivers also in stock.
Ordered the shipment last week. It was shipped on Thursday and this morning DHL delivered....Some service.

Happy Chineses New Year!
See you all my friends

Our Breakout Board is coming
[email protected]

Any spec's yet that we can have a look at. USB or Parallel ? How many axis ? We NEED to know.

Hey, Master Kobus.
Our BOB are Parallel and at most 6 axis including spindle motor.

I am glad that more than one year ago, I lauched this ad. And UIROBOT stepper driver, stepper controller win lots of users' appraisal.

[email protected]
[email protected]

This is Tiger from UIROBOT that we release UIM2901-5A Breakout Board for Mach3.
3, 4 and 5 axes CNC solution:
DC Power Supply
Parallel port Mach3 Breakout Board
3, 4 or 5 pieces UIM24002/24004/24008 Pulse&Direction stepper driver.
Nema17 0.44N.m, 0.65N.m and Nema23 1.26N.m, 1.89N.m stepper motors.

L Flange for double shaft stepper motor.
http://farm7.static.flickr.com/6156/...ea3fcf47_m.jpg

Happy New Year 2012

Same to you, now you are also in 2012 :D