UIROBOT Stepper Drives

[uirobot]

Hey:D
This is Tiger Huang from Shanghai, Product Manager of Stepper Motor Controller. Our Product Engineer Doctor Zhu who study and work in the USA developed a size coin, which is only 1.665*1.665*0.53 inch Stepper Motor Controllers with Microstepping, RS232 or CAN (protocol).
http://www.uirobot.com/userfiles/240_06.jpg

Welcome communicate with us tiger@uirobot.com Thanks!

[domino11]

This does not look like it would be of much use to a Mechmate builder.

[Gerald D]

Tiger, we need to drive at a minimum of 3 Amps and 40Volts - can you do that?

[max.elliott]

http://www.uirobot.com/robot-archive-a-344.html

Yes they can.

Well, to be fair, they claim they can. 8A 40vdc max. Sites in chinese, but some of the specs are in english. If they can send me 6 for testing..... :)

Edited to add: The drawings indicate they are meant to me mounted on the back if the NEMA motors. This would present some redesigning of the electronics.

[Kobus_Joubert]

Me too me too.. I will test them for FREE :D
Please send them to South Africa Mr. uirobot I will test them on a Mechmate in the HOT South African conditions.

I will take the 8A version..

Translation of the web-page

UIM24002/UIM24004/UIM24008 is a series of ultra compact high-performance stepper motor drives. Its greatest features a small volume, driving skills. Plus the corresponding flange, be fixed directly to the 42/57/85/110 of stepper motor. Its thickness less than 14 mm. UIM24002 can provide 0-2A adjustable peak current; UIM24004 can provide 0-4A adjustable peak current; UIM24008 can provide 0 ~ 8A adjustable peak current. Its high speed current compensation feature, be compensated high-speed rotation back-EMF. This series of drive use 10V-40V DC power supply.

[uirobot]

Tiger, we need to drive at a minimum of 3 Amps and 40Volts - can you do that?

Absolutely we can.
Welcome contact us tiger@uirobot.com for specific information.
Using our CAN protocol stepper controllers, you can control at most 112 motors at a time. Who can tell me how many axis?:p

[uirobot]

http://www.uirobot.com/robot-archive-a-344.html

Yes they can.

Well, to be fair, they claim they can. 8A 40vdc max. Sites in chinese, but some of the specs are in english. If they can send me 6 for testing..... :)

Edited to add: The drawings indicate they are meant to me mounted on the back if the NEMA motors. This would present some redesigning of the electronics.

You know Chinese? Great:D
Our English version website is under construction. Our Product Engineer Doctor Zhu is going to open an branch company in the US.

[max.elliott]

You know Chinese? Great:D
Our English version website is under construction. Our Product Engineer Doctor Zhu is going to open an branch company in the US.

I know HTML and Google translate. I'm rather hopeless at Chinese. I can correct poor english though, if you're looking to hire a final editor. Or a controller tester... ;)

[bradm]

I think the key question is how to integrate these CAM or RS232 protocol drivers into Mach3 or EMC2.

Tiger, we normally use four motors on three axis. The X axis uses two motors. In some cases, five motors are used for four axis.

Can you tell us more about how these motors are interfaced to a (standard Windows) control computer, please?

[javeria]

and yes whats the current pricing :)

[Richards]

There are a lot of factors that are hiding in the background. Most of us use the Geckodrive products, particularly the G203v, which has 2000 steps per rotation, automatic current reduction, LED indicator (yellow) that shows when the drive is pulling too much current, and fail-safe operation that protects the user from self-inflicted self-destruction.

What does this drive offer that the Geckodrive does not offer?

[Tom Caudle]

There are a lot of factors that are hiding in the background. Most of us use the Geckodrive products, particularly the G203v, which has 2000 steps per rotation, automatic current reduction, LED indicator (yellow) that shows when the drive is pulling too much current, and fail-safe operation that protects the user from self-inflicted self-destruction.

What does this drive offer that the Geckodrive does not offer?

If their input is CAN (Commercial Area Network) OR RS232 then you can't use them with any Step & Dir signaling. I have seen several of these type drives out there but they take custom control software that talks to the drives serially and sends them motion commands rather than S & D.

It's hard to design the solution when you don't understand the porblem (:-)

TOM Caudle

[KenC]

Had a quick glance at the specs,

0~40V operating voltage
There are 3 models, 0~2A, ~4A & ~6A.
Selectable peak current,
current compensation (??).
Selectable 1, 1/2, 1/4, 1/8, 1/16 micro steps, (i.e. 3200step/rev.)
uses step, dir, Ena.
Opto input

I'm bilingual so hope this quick summary will help someone.

I don't think you need to know how it interface with Windows, really... who can do that???

[Kobus_Joubert]

I received more info from them in pdf format. They have 3 types....CAN, serial and parallel. Just like Gecko they can also have STEP DIR and ENABLE pulses from your BOB.

9167

9168

9169

9170

[Kobus_Joubert]

Price for UIM24008 is 120USD/PC and price for UIM24004 is 80USD/PC under 10pcs.

I am sure the 4 Amp model at US$ 80.00 will do for me....if I go that way

[KenC]

Sounds good to my bank too :)

[isladelobos]

and about electrical noise? and wire lenght?

[KenC]

I do see some advantages, by mount the driver on the motor, we will eliminate any potential noise within the control panel, just wire the DC power & smaller shielded signal wires from the bob to the motors.

Cheaper cable cost as we can use cat 5 instead of those expensive big 1mm2 shielded power cables... the power cable can be a 2 core 1.5mm2 normal cable....

Maybe we don't even need the cat5 for the signal to the motor...

Maybe we can build (smaller) dedicated power supply units & install them right next to each motor....

[Gerald D]

If their input is CAN (Commercial Area Network) . . . .

I think the CAN would be the Controller Area Network (http://en.wikipedia.org/wiki/Controller_area_network) protocol that was started by the automotive industry and which has very quickly become the dominant network protocol technology there.

[domino11]

Ken,
Don't forget thought that yes you move the drivers out of the control box, but now those low voltage step and direction lines are now big antennae and if not shielded well, they will pick up loads of noise and cause you much grief.

[KenC]

Heath,
So some CAT5 cable should sort that out? Still a big saving on the cable.

[domino11]

Cat 5 is not shielded cable. It is only twisted pair. I would not like to count on that to keep 5v logic level signals free of noise. Shielded cable would still be the way to go for that.

[KenC]

My mistake. Then low cost shielded microphone wire should do the job then.

[Richards]

Let's review some basics.

1. On most systems, a PC is connected to a controller through a parallel cable. To keep electrical noise to a minimum, the power supply in the PC is grounded to the PC's case and the case is grounded to the main ground lug on the controller. Usually ribbon cable is NOT used to connect the PC's parallel port to the controller because of noise problems, instead a good quality, shielded round cable is used.

2. Most controllers use a break-out-board to amplify the signals from the parallel port. On most systems, either the break-out-board or the actual stepper driver uses opto-isolation on the step/direction signals. The length of wire between the break-out-board and the stepper drivers is usually less than 36 inches. All of that wiring is inside a metal case that is grounded to the master grounding lug.

3. Most systems use a stepper power supply that is isolated from the computer's power supply. Only the grounds are connected, so noise from the stepper power supply will not affect the computer's power supply or the break-out-board's power supply.

4. The cables connecting the stepper-drivers to the stepper motors are high quality shielded cables with the shield wire connected to the main grounding lug on the controller.

That type of system is robust and reliable. Electrical noise problems can be controlled by proper grounding. If all inputs to the break-out-board are optically isolated and all outputs from the break-out-board are optically isolated, you will have done just about everything that you could possibly do to minimize most forms of electrical noise.

(Look at the schematic of the G540 mother board to see why it is so reliable. All signals are optically isolated from the outside world. The schematic is posted on the Geckodrive forum on Yahoo groups.)

If you mount the stepper drivers directly onto the stepper motors, in my opinion, you will introduce problems into the system. The low-voltage step and direction signals will have to travel a long distance between the controller and the motors. Those signals will be passed between the controller and the stepper drivers on cables that lie in a cable path that is only an inch or two away from the cable that powers the router or spindle. The little 5VDC signal going to the stepper drivers will have to compete with the large 120VAC or 240VAC signal going to the router or spindle. Remember that an AC signal is measured using RMS, so a 120VAC signal is really 1.414 X greater, or 170V peak to peak. A 240V signal is 340V peak to peak. Also remember that a 5VDC TTL signal is considered good if the low level is less that 0.7V and the high level is greater than 2.2V, so the actual signal range can be as small as 1.5V! What chance does 1.5V have against a 340V peak to peak spindle signal?

There are ways to ways to handle that situation. If you put optically isolated line-drivers on both ends of the step/direction cable and then use shielded twisted pair cable to carry the signals, you will have a better system. If you use fiber optics between the controller and the stepper drivers/stepper motors, you will have a better system. Both methods are complex and possibly very expensive.

For our CNC routers, having good quality stepper drivers mounted inside the controller that are optically isolated from the break-out-board, is the least expensive, most reliable system available to the average user who hasn't spent most of his life tinkering with electronics. Mounting the stepper driver directly to the stepper motor can introduce a lot of noise problems that will not be easy to fix.

[bradm]

Ken, I mentioned a "windows" computer way back in an effort to express the idea of a standard PC that could be running Linux and EMC2, or Windows and Mach3, as opposed to a dedicated machine control computer of one kind or another. This would be particularly relevant in a CAN bus system, which would likely be very robust if you found a way to get it working with our current GCode engines.

Now that it's clear that there is an option for a step/direction interface, how to connect it is obvious. How to connect it reliably is less obvious, as Mike points out. It strikes me that one straightforward solution would be to acknowledge that most of our machines have TWO umbilicals running to the Y car via different routes, and so relocating either the high voltage or the low voltage lines onto the dust collection tube would reduce the noise problem. Another cute idea is to move the stepper power supply onto the gantry. You're still going to want to star wire the power to the drivers, and this will save on the wire lengths.

In terms of competitive cost, we're still at 4 * $80 + ?? for a Bob = $320+ for a set of these, supplying 40V * 4A = 160 watts per motor. Compare that with G540 at $300 for a Bob and 4 drivers supplying 50v * 3.5A = 175 watts per motor.

I was hoping to be able to demonstrate that a CAN bus interface would be practical for our application, but just like with USB, the latency is killer. CAN bus can run up to 1Mhz, and a worst case message takes 134 bit times, or 134 microsec. Assuming a clean CAN bus constantly sending signals to four motors, we're at a cycle time of 134 * 4 = 536 microsec = about 2,000 updates per second. That would be not quite 200 IPM on a 10 microstep ungeared motor. Too slow for bit twiddling, and once you move beyond bit twiddling, the integration with Mach or EMC gets rather complex.

These drivers are an interesting solution, and show the potential of the new breed of driver chips ( See also Allegro ), but they aren't yet a complete solution for our application.

[KenC]

Mike, Brad, Thank you so much for elaborating. Really helps. Before this I only have a faint idea of what to do with our MM electronics, now, I'm getting a clearer picture of what I'd done correctly on my control system. Still need more time to digest the information fully before I throw out more stupid questions.

Thanks again, really appriciate it.

[bradm]

Ugh, and I made two errors. One, the step signal needs to go on and off for a full cycle, which is two updates, and two, Nyquist sampling limits, which are also approximately 2 to 1. So in my hypothetical CAN bus case, it's actually less than 500 updates per second, which would be under 50 IPM on an ungeared motor, and closer to 10 IPM on our common configurations.

[liaoh75]

Hey guys, Mounting directly on the motor?? What about heat buildup? Wouldn't the driver and stepper be frying each other on a hot summer day in the shop? Or, did I just ask a stupid question?:D

[max.elliott]

Hey guys, Mounting directly on the motor?? What about heat buildup? Wouldn't the driver and stepper be frying each other on a hot summer day in the shop? Or, did I just ask a stupid question?:D

It's a good question! Anyone have a theory?

[KenC]

How about Don't run your motor too hot...

[uirobot]

About the heat. We have tested too much, if you motor generate heat much higher than 70 degree, we would say your motor is bad one or bad condition.
Our Stepper Motor Controller with aluminium heat sink enclosure and thermal grease and so on for heat dissipation, the controller itself generate little heat.

[liaoh75]

Uirobot, does that mean your stepper driver can take 60-70 degrees C day in and day out on the back of a NEMA 34 body stepper? Isn't that pretty close mil-spec thermal ratings? I know mil-spec rated PLCs have to be able to take 70 degrees for a set amount of time but not indefinite. My OM 7.2 geared 296 motor runs at about 50-60 degrees easily in the summer time. My Geckos in a well ventilated cabinet hums along at about 40-45 degrees when the ambient temperature is about 33-35 degrees C. I don't know of too many electronic goods being able to take that kind of punishment long term.

[uirobot]

Uirobot, does that mean your stepper driver can take 60-70 degrees C day in and day out on the back of a NEMA 34 body stepper? Isn't that pretty close mil-spec thermal ratings? I know mil-spec rated PLCs have to be able to take 70 degrees for a set amount of time but not indefinite. My OM 7.2 geared 296 motor runs at about 50-60 degrees easily in the summer time. My Geckos in a well ventilated cabinet hums along at about 40-45 degrees when the ambient temperature is about 33-35 degrees C. I don't know of too many electronic goods being able to take that kind of punishment long term.

I really appreciate your question. I am the Product Manager not Product Engineer:D. But I want to tell you that we tested our UIM24008 Stepper Motor Controller clockwise setting the current 8A and after we measured out the tempreature of our Controller is 68 degrees while the motor tempreature is higher. What I want to tell is that we design our products strictly according to our technical figures given out but for different application, we are glad to have your reports. Thanks!

[uirobot]

I like this wonderful forum, I am a fishing website owner I wrote on my website that I'd think a forum to spare spams the best way is setting a area for ads. In my eye you and I will find some related ads are useful.

Sorry, a little far away. Our English website is coming soon, now the User Manual of our stepper motor controllers are available in English. If you wanna take a look, please write me letters to tiger@uirobot.com

[uirobot]

I think the key question is how to integrate these CAM or RS232 protocol drivers into Mach3 or EMC2.

Tiger, we normally use four motors on three axis. The X axis uses two motors. In some cases, five motors are used for four axis.

Can you tell us more about how these motors are interfaced to a (standard Windows) control computer, please?


Hello Bradm,

First thank you for your question. Our stepper motor controllers are integrally mounted onto motor through corresponding flanges. If your motor have rear shaft, a "L" type flange will be needed.

To control many motors at different Axis, you may adopt our CAN protocol stepper controller. A CAN/RS232 Converter is needed here. One Converter could at most connect to 112 motor at the same time and then be connected to your computer, you give out orders, we have Global Command so you can drive your motors synchronous. Also you can drive one by one.

UIrobot
Tiger Huang
tiger@uirobot.com

[uirobot]

There are a lot of factors that are hiding in the background. Most of us use the Geckodrive products, particularly the G203v, which has 2000 steps per rotation, automatic current reduction, LED indicator (yellow) that shows when the drive is pulling too much current, and fail-safe operation that protects the user from self-inflicted self-destruction.

What does this drive offer that the Geckodrive does not offer?

Richard,

Thank you for your feedback!

Our UIM 240 Series may do all the work Geckodrive can do.
UIM 241 with RS232 and UIM 242 with CAN will different from theirs. UIM 241 and UIM 242 Series are standalone, you don't need an extra controller to control driver. We can control at most 112 motors at the same time using UIM 242 Series and the CAN/RS232 Converter.

I am glad to send you our User Manual if you wanna know much more. Thanks again.

UIrobot
Tiger Huang
tiger@uirobot.com

[Gerald D]

. . . I'd think a forum to spare spams the best way is setting a area for ads. In my eye you and I will find some related ads are useful. . . .

The limit is to have only one thread per advertiser. Your new thread has been joined to this one.

[uirobot]

and about electrical noise? and wire lenght?

RS232 100M and CAN protocol 10 killometers.

[uirobot]

The limit is to have only one thread per advertiser. Your new thread has been joined to this one.

:DThat's fine.
Here I claim that our User Manual in English are available, welcome asking for a look. Our Stepper Motor Controllers are 14 non-condtional refundable and changeable.:p

[liaoh75]

Uribot, would you be willing to post a video of your drivers working (mounted on the back of the stepper) with nema34 steppers running under Mach3?

[uirobot]

Uribot, would you be willing to post a video of your drivers working (mounted on the back of the stepper) with nema34 steppers running under Mach3?

I am sorry that we cann't run under Mach 3.

[Kobus_Joubert]

Don't you have Mach3 or is your drivers not capable ? Mach3 takes in standard G-code. I not understand.

[bradm]

Kobus, as suspected above, it appears that these drivers will not accept a simple step/direction signal. They can be controlled via RS-232 or CAN bus. Both of those are too slow to transfer the pulse train that Mach3 and/or EMC2 generate.

There's an outside chance that with serious software rework, someone could write a (software) driver for these that sent the higher order commands from the trajectory planner inside Mach3 or EMC2, but that would be a lot of work, and has not been demonstrated successfully in other attempts. The issue is that keeping the movements of multiple axis in precise synchronization while using a slow communications link is extremely difficult.

[Kobus_Joubert]

I am not so sure. I think he is shoothing himself in the foot.

From the data in previous post nr.14 this is what I see.

9243

[bradm]

True, that would work, assuming you find a way to get the signals there.

[Kobus_Joubert]

No problem, leave the controller in your box and only extend the motor wires like we do in any case.

This thing does not have to be mounted ON the stepper, even if it has the facility.

[normand blais]

they dont even need to be in the box

[uirobot]

Don't you have Mach3 or is your drivers not capable ? Mach3 takes in standard G-code. I not understand.
I am sorry that I don't know Mach3.:)

[uirobot]

Kobus, as suspected above, it appears that these drivers will not accept a simple step/direction signal. They can be controlled via RS-232 or CAN bus. Both of those are too slow to transfer the pulse train that Mach3 and/or EMC2 generate.

There's an outside chance that with serious software rework, someone could write a (software) driver for these that sent the higher order commands from the trajectory planner inside Mach3 or EMC2, but that would be a lot of work, and has not been demonstrated successfully in other attempts. The issue is that keeping the movements of multiple axis in precise synchronization while using a slow communications link is extremely difficult.

High speed RS232: 115200 bps
high efficient CAN (UI CAN): 1M bps
One full CAN message takes: ~100 micro seconds (tested)
total node number x: ~100 (designed for, not tested)

[bradm]

100 microseconds = 10,000 updates per second.

200 steps/rev stepper motor at 10 microsteps = 2,000 steps per revolution.

10,000 / 2,000 = 5 revolutions per second = 300 RPM on the stepper motor.

Assuming 20 tooth, 20 pitch gear on a MechMate = about 3.14 inches per revolution. Times 5 revolutions per second is 15.7 inches per second or 942 IPM.

That sounds good, until you factor in updates to 4 or more motors on that bus, and you're down to 235 IPM or less, and that's assuming perfect performance.

And that is direct drive, and we generally have either gearbox or belts in the range of 3.6 to 7.2 to 1. So cut that down to 32 to 65 IPM. That's very slow.

Even with a dedicated CAN bus for each motor, it's still only 128 to 256 IPM.

Somebody check my math, I've been mistake prone lately ;)

[uirobot]

I think the key question is how to integrate these CAM or RS232 protocol drivers into Mach3 or EMC2.

Tiger, we normally use four motors on three axis. The X axis uses two motors. In some cases, five motors are used for four axis.

Can you tell us more about how these motors are interfaced to a (standard Windows) control computer, please?

USER <<==High speed RS232==>>UIM250 Converting Controller <<== high efficient CAN (UI CAN) ==>>UIM242xx Motor Controller (Node 1) <<== high efficient CAN (UI CAN)==>> UIM242xx Motor Controller (Node 2) ...<<== high efficient CAN (UI CAN) ==>> UIM242xx Motor Controller (Node x) .

[uirobot]

There are a lot of factors that are hiding in the background. Most of us use the Geckodrive products, particularly the G203v, which has 2000 steps per rotation, automatic current reduction, LED indicator (yellow) that shows when the drive is pulling too much current, and fail-safe operation that protects the user from self-inflicted self-destruction.

What does this drive offer that the Geckodrive does not offer?

Richards,

Our UIM 240 Parallel Model is a driver, UIM 241 Serial and UIM 242 CAN protocol are intellegient controller, no need extra control card or so. UIM 242 can control synchronous 112 motors at most, who can make it.:D

[uirobot]

I do see some advantages, by mount the driver on the motor, we will eliminate any potential noise within the control panel, just wire the DC power & smaller shielded signal wires from the bob to the motors.

Cheaper cable cost as we can use cat 5 instead of those expensive big 1mm2 shielded power cables... the power cable can be a 2 core 1.5mm2 normal cable....

Maybe we don't even need the cat5 for the signal to the motor...

Maybe we can build (smaller) dedicated power supply units & install them right next to each motor....

Yeah, Ken
You do not need shielded power cables and even the cat 5. Normal cable with do all the work. It can connect User Device by RS232 cable with DB9, DB15 or DB25

[liaoh75]

Do you have a model that will work with Mach3 and take step and direction pulses?

[Kobus_Joubert]

I think this one will do it at 4 Amp David
UIM24004B
1-9pcs 48USD

[danilom]

Look on this page

http://en.uirobot.com/robot-archive-a-357.html

Communication: 3-wire, Step, Direction, and Enable signals
DIR, SPD, CUR, STP, Microsteppers

UIM240XX Stepper Motor Controller

[uirobot]

http://en.uirobot.com/upload/archive_pic/1/1274928868.jpg
UIM24302 Parallel Micro stepper motor controller

Product Feature:

Micro Size, 16mm*24mm*2.5mm
Embedded stepping pulse generator, adjustable frequency
ON/OFF, Reset, Direction 3-wire control
10-35V DC, 2A adjustable phase current, 16 microstepping
TTL Logic control

[Kobus_Joubert]

I found more info on the UIM24004 driver....the one that will take STEP and DIRECTION pulses.

http://www.slidesandballscrews.com/pdf/UIM240%20Manual%20_English_%20_2_.pdf

In the documentation is states:

Low-Level pulse duraion should > 8 uS
Max Pulse frequency is 50 kHz

How does this compare to the Gecko ?

[Gerald D]

Kobus got his MM to run on UI Robot drives today (http://www.mechmate.com/forums/showthread.php?t=686).

[Richards]

The Geckodrive G203v requires a minimum High-Level pulse of 2uS. It has a Maximum Pulse Frequency of 333kHz.

SPECIFICATIONS:
Supply Voltage: 15 to 80 VDC
Phase Current: 0 to 7 Amps
Auto Current Reduction: 71% of set current, 1 second after last Step Pulse
Size: 2.5”W, 2.5”D, .85”H (63.5mm, 63.5mm, 21.5mm)
Mounting Pattern: 4 6-32 screws, 1.75” by 2.375” (44.5 mm, 60 mm)
Weight: 3.6 oz. (100 gm)
Quiescent Current: 20 Ma or less (drive disabled)
Short-circuit trip current: 10A, 3uS response time
Step Frequency: 0 to 333 kHz
Step Pulse “0” Time: 2uS min (Step on rising edge)
Temp: 0 to 70 C
Step Pulse “1” Time: 1 uS min
Humidity: 0 to 95 % (non-condensing)
Direction Setup: 200nS before step pulse rising edge
200nS hold after step pulse rising edge
Power Dissipation: 1 to 13 W (0 to 7 Amps)

[liaoh75]

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.

[bradm]

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.

[smreish]

...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

[uirobot]

http://www.cam-mobi.com/UIM-stepper-motor-controls-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-rs232-stepper-controller.jpg
Programmable stepper motor controller

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

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

[uirobot]

Shanghai Expo
Stage lighting design by stepping motors.

[uirobot]

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_pic/1/1274149404.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.:)

[Kobus_Joubert]

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.

[Kobus_Joubert]

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.

[uirobot]

Happy Chineses New Year!
See you all my friends

[uirobot]

Our Breakout Board is coming
tiger@uirobot.com

[Kobus_Joubert]

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

[uirobot]

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

[uirobot]

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

[uirobot]

TIGER@UIROBOT.COM
UIROBOT@YAHOO.COM

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.

[uirobot]

L Flange for double shaft stepper motor.
http://farm7.static.flickr.com/6156/6260194976_46ea3fcf47_m.jpg

[uirobot]

Happy New Year 2012

[Kobus_Joubert]

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