Note that you can only get about 1.4A/phase out of this driver chip (even though it's rated for 2A/phase) without actively cooling it and heatsinking it. Even with those, it's hard to get close to 2A/phase.

That being said, I've yet to find an application where 1.4A/phase wasn't good enough but 2A was. Normally, for applications where you absolutely need the very maximum torque of your big hoss motor, you're going to opt for much more robust and powerful drivers like Geckos.

Also note that you can't damage this board by over heating it. (This is not a challenge. ) The driver and voltage regulator have built-in over-temp circuits that will cut out their outputs if they get too hot. You'll notice that the motor will start to 'stutter' if the chip gets too hot. Just back off the current adjustment pot in this case to send less current to the motor.

Some users have trouble getting smooth microsteps. I always tell them to start with a nice slow pulse rate - maybe 10Hz or lower, and feel the shaft of the motor with their fingers as it's rotating. At 16x microsteps, you may feel there are some steps that are more or less powerful than others. Adjust the current limit pot, or increase the input voltage, if you have trouble getting smooth micosteps.

Also note that if the coil resistance of the motor you have chosen is too high, the BED can't create microsteps properly. If you raise the input voltage, that will help solve this problem. Or just use a motor with lower coil resistance.

Under normal usage, this driver can push a substantial amount of current through the motor - especially when it's not moving. The motor can and will get quite hot. I've not burned myself on a motor (yet) but I've gotten close. Be careful. Even at 1A/phase @12V, you're dissipating 24W in that motor.

The amount of current you see being drawn through your power supply is NOT the same as the current going through the motor coils during motion. So if you're stepping, and you see 500mA being drawn from your 24V power supply, that does not mean that each coil is getting 250mA. You have to measure the TP3 test point with a meter, and use the formula in the data sheet to figure out the actual maximum current through each coil. Typically the current through the coil will be much higher than the current drawn from the power supply because of the chopper circuit on the BED.

*Brian

I'm using BED and I'm very exciting with works. You can see photos and videos of first test at fb.com/protoptimus.

So, now I need to more speed. My "leadscrew" has 1,5mm pass per revolution of motor.

I'm using a 12V power supply, and default BED with no jumper configuration. I mean, I guess the BED is in 1/16 microstepping by default.

I will use now a 24V power suply. My question is: I have to put the BED in full stepp mode to get more speed?

And if yes, how I do this? It's just jumper the MD1-3 to GND? Or I have to cut of some trail of the board. I have no ideia to how chance between High and Low the MD1, MD2 and MD3 pins, because, I think the BED in default is in High, so, if I connect the MD# pins to GND to put them LOW, I will make some thing wrong?

Sorry my english.

Hi,

my big easy driver recently stopped working. When i measure the signal on the motor outputs i just get the same voltage as the powersupply (5V) even though i have the stepper and direction as well as ground inputs connected.

shouldnt i get some rectangular signal from the motor outputs?

Now the outputs A,A',B,B' are all 5V if powersupply is turned on and 0V if turned of. Is this a sign of a burnt chip`?

Hi all,

Has anyone had a problem reversing direction when in any of the microstep modes? I can change direction without problems in full step mode, but any time I run in microstep mode I cannot get the motor to change direction, regardless of setting the direction pin high or low. It always runs as if the direction pin is high. Any ideas or suggestions please?

Just a quick question -

I am going to be using the PRT-11510 Small Heatsink. Where should I place it? On the top or on the bottom where all the thermal pads and vias are? It seems to me that with this design the bottom would be better.

Regards JohnK

I see a few of these have been blown. Looking at the data sheet the equation for max current is I_max = V_ref / (8*R_s).

The board schematic and features list say the current adjust pot will give you 0 to 2.4 Amps.

However, if using the board at 5V logic level I get the max current to be 4.5 amps since you can put a max of 4V on the V_ref pin (unless the adjustment pot is limited) and the R_s resistors are 0.11 ohms. Now I'm sure it can't actually do 4.5 amps, but it's definitely allowing it to run completely maxed if not over-run.

On the website the old version 1.1 has R_s values of .22 ohms and you can put up to 4.2V on V_ref. This setup works out to exactly 2.4 amps.

What am I missing? Why the change?

I've blown two of these boards. Anytime the motor stalls. I've used fast blow fuses on the motor wires, the power input, pretty much anything I can think of. I will not be buying a third. For $10 more you can get the SideStep from Probotix. They use the much larger Allegro chip. That chip is what most CNC's controllers use unless they spring for discrete electronic boards like the geckos. I wouldn't use this for anything serious.

guys im still having a hell of a time getting this driver to drive...

I was able to get the motor to step using a ULN2003AN connected to my arduino but when i use the BED all i get is studdering back and forth... Every once in awhile it will drive one way then sporadically change direction..

Ive tried two different power DC supply's.. One 12V @ .5A and 30V @ 1A and i get the same results with both...

Ive double and triple checked my wiring config and its correct..

Ive adjusted the POT with no avail.

I connect pairs A to A pairs B to B and leave the center coils disconnected.

Ive tried every stepping mode the board offers and the default 1/16 microstepping mode is the only one that gets close to operating the stepper

Ive used several different librarys including the AccelStepper to no avail..

the stepper im using is a Japan Service Co. KH42JM2 NEMA 17 series stepper... Its rated for roughly 4.95V @ .85A in bi-polar config and ive read over and over that 12V @ 0.5A should be sufficient and that you can over volt the crap out of steppers..

I also tried a stepper out of an old printer and again, the same results.

Can anyone offer any assistance? What am i missing here?

Motor Datasheet: http://www.japanservo.co.jp/digital/english/general/pdf/KH42J.pdf

Uh yep... Mine fried as well.... Bought another one but it appears that was a mistake and a waste of another 24.00... This thing is junk... Take the advice of the developer himself and go with a Gecko driver...

I have a Big Easy Driver that works great in one direction but won't reverse. Even with very simple code that changes the dir pin to HIGH or LOW doesn't move the motor backward. This code doesn't even get it to turn. (sorry for formatting issue)

void setup() {
pinMode(3, OUTPUT);
pinMode(9, OUTPUT); digitalWrite(3, LOW); //LOW does not run but HIGH runs counter clockwise digitalWrite(9, LOW); }

void loop() { digitalWrite(9, HIGH); delayMicroseconds(100);
digitalWrite(9, LOW); delayMicroseconds(100);

}

What is the maximum step speed?

Hello, Is it possible to reach 400RPM and more, with that driver and this stepper motor? http://catalog.orientalmotor.com/item/all-categories/pk-series-stepping-motors/pk266-02a

Hi! I need to lift and hold 10kg (with slow movement). I am looking for this stepper motor with big easy driver. Any advice for this task? Is the driver and this motor a good choice?

Is Big EasyDriver good for driving this ->Nema 23 CNC Stepper Motor 2.8A 1.26Nm(178.5oz.in) ?

Yep: Another unsatisfied customer. I seem to be having the same issue with the BED that others have reported. After hooking up my motor and power supply exactly as directed, it ran choppily for a few moments, then stalled. Then the board seemed to stop working entirely. Now, as soon as it's powered on (with no motor hooked up), the LED glows momentarily, then dims, then goes out. What's up with that?

I need to run a bipolar stepper motor (Minebea 16pu-m202) v e r y s l o w l y for hours at a time, off a battery. Is there any reason I couldn't use a very simple, low-frequency pulse-generator circuit (using a 555 timer, for example) to run this driver?

Hello all. I recently purchased the Big Easy Driver and I love it. I was wondering the code is to 'release' the stepper? It's building up heat while it sits idle. Thanks, Jon

Hi I bought 2 of these little guys to driver two 125 Oz in. I bought here also. After wiring them up I ran the example code from Bildr tutorial and i got it to move but it was kind of jerky so in an attempt to get it to run smoothly I turned the current adjusting pot one way and the other and suddenly the horror! Magic smoke all over the place! i even saw a glow on the little BED! This happend to both my circuits :( Im kind of new on driving stepper motors so any help as how can I set up the correct amount of current from the pot will be very much appreciated.

I was supplying 12V the first time and 20V the second. Im looking for the max torque i can get from the stepper.

Thanks!

Just to save people some work, here's how to set the max motor current:

Vref = 8 x Rs x Imax = .88 x Imax

Rref = 8 x Rs x Imax x Rtot / Vdd = 2.1982 x Imax

where:

• Imax = desired max motor current
• Vdd = logic supply voltage = 5 V
• Vref = voltage on REF pin, set by the voltage dividing pot
• Rs = sensing resistor = .11 ohm
• Rref = resistance on the low side of the pot wiper
• Rtot = total resistance of full pot plus limiting resistor = 12.49 kohm

For your convenience, here's a table of values based on the current board design and Vdd = 5 V, in 0.25 A increments:

Imax    Vref    Rref (k ohm)
0       0       0
0.25    0.22    0.55
0.5     0.44    1.1
0.75    0.66    1.65
1       0.88    2.2
1.25    1.1     2.75
1.5     1.32    3.3
1.75    1.54    3.85
2       1.76    4.4

I can't get the BED to run my stepper motor :/. I conneted everything the same like in this tutorial http://bildr.org/2012/11/big-easy-driver-arduino/ but the only thing my stepper is doing, ist stepping one step clockwise and one counterclockwise. My PSU has 12 V /1,5A. The stepper is a NEMA 17 rated with 12V / 0,4A. I also tried it with a more powerful PSU rated @ 24V /2.7A an a 24V stepper with 1A but still the same problem.

Can someone help me out here :) ?

I've noticed a few comments here lately from people who had trouble with the BED. Therefore, I am going to add my experience to the official record. I bought two BED's in the past 3 months (about a month apart.) One of them worked perfectly, but the other behaved much like those described in posts below: choppy, inconsistent motion. Note that I have been able to precisely compare the two BED's with the exact same motor and hook-up (NEMA 23, 1A and 7.4V per phase). Just prior to my posting this, the defective board went up in flames (literally). To whomever it may concern, it might be time to investigate whether a particular batch of BED's is flawed.

Hi

im thinking of building myself an arduino controled CNC machine to learn some new things (and end up with an usefull tool for future projects ;P) but im wondering if its possible to connect 3 of these to an arduino to control my XYZ axis and if yes how? i cant seem to find a schematic for it online...

Would anyone know what the best rotary encoder is to use with this driver?

Hi,

I recently buy this driver, with a NEMA 23 stepper motor, and with Arduino, I have tried to move it, but I can not. I have used a circuit similar to reprap 3d printer (Arduino controls ENABLE, DIR and STEP) and the other pins are fixed, but the motor does not move. I have noticed that the voltage regulator, it is heated up, so I think this component is damaged. Is there any way to check I am correct? Are there other explains? What is exactly the voltage regulator for replace it?

Thank you very much, Antonio.

has any one connected any screw terminals or does every just solder header pins to this board ? thanks

In the description, it says "maximum motor drive voltage of around 35V". Unfortunately the only affordable switching power supply I could find are 36v. Do you think it could handle it?

Cool that Brian is actively commenting here. Thanks!

This looks like a great board. Wish there was a breakout or adapter that allowed it to plug and play with the Polulu sockets commonly found on RAMPS and other reprap boards. More options the better!

K

I am attempting to drive a Karlsson 267 oz-in Stepper Motor using a Allen Bradley PLC to drive an automated book scanner system. The stepper is rated for 2.8A (I thought this meant 1.4A/phase, which made the BED an option). The PLC has 24V transistor outputs hooked to STEP, DIR, and GND. I used a voltage divider of R1 = 1.5M and R2 = 330k to yield V input = 4.34 V and I input = 16uA to meet the specs per the A4988 datasheet so I don't see the PLC being the issue. M+ is hooked to a 24VDC power supply.

When I first ran the program, the BED was fine and the stepper was making sound but did not step. Per the directions in the user manual, my next step was to adjust the current pot. I used a multimeter to GND and TP1 to get reach a Vref = 1.76, to reach the max 2A. The stepper started to sound closer and closer to actually stepping as I turned the current up. During the process of adjusting the pot, the board turned off. I assumed it got too hot and the voltage regulator temporarily shut it down. Now every time I power up the board, I hear a quick pop, the LED go bright and depending how long it has been sitting, it dims out and board is off - this usually takes between 1-3 seconds after power up. The component nearest the motor pins gets very hot if I leave the power supply turned on to the board. The board quickly turns off regardless of where the pot is set.

Is this board fried or is it overheating? How do I correct this issue? Heatsink?

Is the board compatible with my stepper or do I need a different driver board? If I need something else, is the Probotix SideStep driver a compatible board for my application?

Any and all replies are gladly appreciated, I am very ready to solve my stepper woes.

EmbeddedMan PLEASE HELP.

Here is the link for my stepper: http://www.karlssonrobotics.com/cart/Stepper-Motor-267-oz.in-Dual-Shaft-NEMA23-200-steps-rev/