How to set VRef for A4988 and DRV8825 stepper motor drivers
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- Опубликовано: 20 июл 2024
- In this video I'll teach you how to calibrate the VRef for the A4988 and the DRV8825 Stepper motor drivers. For the complete blog post visit: zerotohero.engineering/settin...
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Below you can find the links to all the parts and equipment used in this video. By clicking and buying something from the links below you'll be helping Zero to Hero Engineering with no extra cost to you. Thanks!
A4988 Stepstick: bit.ly/3elwqPG
DRV8825 Stepstick: bit.ly/3gWrQZX
Uni-T UT61E Digital Multimeter: bit.ly/38UYcBx
Arduino Mega Clone: bit.ly/3esnkR6
Ramps 1.6: bit.ly/3fsmyoy
S-180-12 12V Power supply: bit.ly/2WfS5CM
42BYGHW804 Stepper Motor: bit.ly/3fsWppB
Precision Screwdriver Set: bit.ly/38QcNya
Crocodile Clips: bit.ly/2OooUsU
Blog: zerotohero.engineering/blog/
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To the moon!
Excellent video, clear, precise, no annoying music and I learnt a lot. Many thanks and keep up the good work
Hi Bearwood. Thank you very much for your kind words and feedback. A new video will be published soon :)
Thanks for not trying to be a comedian while explaining the technology.Getting straight to the point and not wasting words earned you another sub. THANKS!
Perfect training video! Thank you! You are the best! I've been printing for a couple years and this is totally going to save me a bunch of headaches. My driver V-refs were way too low.
Thank you for your kind feedback. I'm happy that it was useful and easy to understand :)
Short and to the point. Well done, very helpful. Thank you.
Many thanks for a professional explanation and presentation. Love to see more.
Thanks! A few new videos are already under production and will be released as soon as they're ready :)
Best video on the subject, well done !!!
Thanks mate, precise and detailed at the same time.
Thank you for your feedback. I''m happy that it was useful to you :)
Uitstekend uitgelegd, ik heb al 2 opgeblazen. Nu heb ik al nieuwe besteld en ben op internet aan het zoeken hoe A4988 en DRV 8825 moet worden ingesteld. Maar nu begrijp ik dat met de stappen motor en de driver eerst goed moet uit gaan rekenen om de Vref in te stellen. Heel erg bedankt van deze Video uitleg.
I had to use google tranlator for this one :) I'm glad it was helpful for you. Thanks for your feedback :)
Very well described, after leaving about top 10 videos i watched this one till end because it was explained very well
Thank you for your feedback! :) Cheers!
nice trick attaching the lead to the screwdriver! thanks
i will be back easy to understand ....no "hi guys welcome to my shop". fantastic.
Thank you for your feedback :)
Thank you! Best Tutorial on this.
Thank you very much, I have a nema17 pancake stepper motor which was over heating. Now thanks to your tutorial I know the problem is excess current!
You're welcome! Thanks for your feedback :)
Superb! wonderful demonstration, thanks!!!
Thank you for your kind feedback! :)
Your style is amazing please make more videos
thanks and keep up the good work, Excellent video!!
Thank you for your kind words. Work has been keeping me from posting new videos, but I hope to publish new ones soon.
Really, really, good tutorial. Thank you.
Thank you for your feedback as well! :)
please continue making video your content is really good
Thank you for your feedback. As soon as some free time is available, more videos will come for sure :)
Awesome explanation . Thank you very much.
Thank you for your feedback :)
Génial super vidéo merci 🤗🤗🤗👏👏👌👌👍👍👍
Seriously, this was a very informative video, and I agree with Bearwood about the music... this did not need it.
Hi Alex M. Thank you for your feedback. The third video of the channel will be published soon :)
Useful information. Well presented and explained.
Thank you very much for your kind feedback! Cheers! :)
merci beaucoup pour votre travail ,video tres bien expliquer vous avez un aboné de plus
Thank you this Tutorial is Perfect..
Thank you for your kind words. We're glad you found it useful
Great video! Thanks!
Glad you liked it. Thanks for your support!
Thank your great help. Got motors to run right; finally. : = }}
I'm glad it was helpful for you :) Thanks!
excellent!! thanks!
Clear and precise
Thank you for your kind feeback! :)
I wish I lived where you live. The ut61e is like 140 where I live. I have the ut61e + and you're right is a great multimeter and I've had many. Thanks for the video too. I forgot how until you said crocodile clips haha
Well I actually ordered it from China. If I had bought it locally it would have been much more expensive. Regarding the "crocodile clips", some people also call them aligator clips. Thanks for the feedback :)
@@zerotoheroengineering are you insulting me? I'm horrible at sarcasm. Lol i was thanking you and probably got the word messed up lol I got mine from China too but they've went way up in price in China. I paid like 110cad. Great meter the probes are no different than any of the probemasters I have. I actually mailed a set to a youtuber in new Zealand. When I ordered them I didn't realize that they were just the probes but they retracted way too easy. I got a new set with all the different parts for Xmas and they send them in a giant case like a good ratchet set would be in but no one keeps their probes in the case. There's a set on Amazon from a company called bionzo for like 50 dollars that I already had. If not for the soft wire on the pm there's no difference in quality. I forgot how to set vref and your channel popped up. I'm only a newb man, 2 years into circuit level components and theory as a hobby. Much more fun than coding. Peace
Thanks for this good video
excellent expression. thank you so much
Thank you for your kind words! :)
well done... THANKS
Nice info, thanks :)
You're welcome! Thanks for your feedback! :)
Great tutorial. Thanks!
Sadly my A4988 jumps from 0,1V by turning 1° directly to 1,7V. No possibility to adjust 0,8V at all ...
Thank you very much for the very informative video. I do understand that for my step motor Nema17 (17HS4401) A4988 should be set to 1.7*8*0.1=1.36, and DRV8825 should be set to 1.7*0.5=0.85
I'm glad it was useful for you! :D
Hi, i am using the same motor with the a4988, but the a4988 maxes out at 1.21, how do i get to 1.36
super,super,super!!!!!!!!!!!!thank you!!!!!!
I'm glad it was useful :) Thank you for your feedback!
Thank You for a Very useful and informative video. I have one related question to ask, will this solve the problem of overheating motors and annoying aound they make?
Hi. Setting the VREF correctly allows you to get the best performance, which means less noise and less vibration. However, there will always be some noite using these motors. There are other stepper motor drivers from Trinamic (TMC2100, TMC2130, TMC2208, TMC2209) that can further reduce the noise and vibration. When I get some time I'll make a video about them. Stay tuned
Best tutorial on Vref!
It should be possible to do this without the ramps board, right?
Thanks for your feedback. Yes, it is definitely possible, even on a breadboard. I just decided to use the Ramps because I already had it and makes everything simpler.
So my question is, why did you select a 12v 180w power supply? I’ve been trying to find out or understand what the minimum power is required.
Can I use 12v with 74W or can I also use 24v @144W? I have been unable to find out how I can possibly use higher voltage power, and how to go about it.
Well done
Thanks! :)
nice sir keep going
Thank you for your feedback! It is very important to know that viewers think about the videos! :)
Well done sir
Thank you for your kind feedback! :)
Great video, very informative and explains WHY for things, rather than just DO this. Can you do one for TMC 2209 too? :-D I notice you only have 2 videos, did you stop?
Thank you so much for your feedback. Regarding the TMC2209, yes. It was already on my plans, actually :) . I didn't stop making videos. I just have been been busy with work and a few projects (some videos about them coming) but didn't have time to edit the videos yet. I didn't stop, just had to pause. Hopefully I can get continue making videos soon :)
The electronic clinic showed the use of the second Vref formula for the a4988. (VRef = Imax/2).
Hello Ryan. The formulas I provide in the video came from the stepstick pages from Pololu and are correct:
DRV8825: www.pololu.com/product/2133
A4988: www.pololu.com/product/1182
The formula they showed you also works for the A4988 as a "rule of thumb" if the Rsense of the A4988 is 68 mOhm. If you do 8x0.068 = 0.544 which is very close to the 0.5 (or 1/2) of the formula of the DRV8825 that you mentioned, making both formulas very similar. However, if the Rsense is different than 68 mOhm the VREF calculated using that formula will no longer be accurate.
@@zerotoheroengineering Thank you. This is useful. I did find the data sheet for the A4988 when I went to your website. I appreciate you sharing your sources.
@@ryanbrown172 You're welcome and also thanks for sharing info here. Cheers!
How would I go about this if my power source doesn't have a positive and negative voltage section like yours does (just one cable for the entire power source)?
If it just has one cable coming from the power source you'll have to strip the insulation of the tip of the cable and there you will find two conductors. They can be two separate wires or one of them can be isolated and the other not. If this is the case, the one that has insulation is usually the positive and the other is the negative. However, the best to do is to test them using the multimeter.
Do you know if the resistors are connected in series ? or parallel? or we just take the value of one resistor
Hi. Just take the value of one resistor :)
Noob here... does this mean that, by setting the imax value with the potentiometer it won't matter how many amps te power supply is sending? Also... is it normal for the driver and motor to get too hot to touch longer than a couple of seconds?
How did you come up with the formula for calculating V_ref? Is this something from the datasheets?
Hello Peter. The formulas came from the stepstick pages from Pololu:
DRV8825: www.pololu.com/product/2133
A4988: www.pololu.com/product/1182
Hi I have a question, I connected the DRV8825 driver the wrong way and I do plug in the power, will that burn down my driver? because I notice that I cannot get any Vref reading after I correct that.
How much the vref setting, if we use two motors with one driver.
Motor description is 10kgcm and 2.8A
And driver is easy driver stepper motor
Hi. The easydriver is not appropriate for your motors since it has a maximum current of 700mA per phase, which is 4 times less than what you need: 2.8A. You should look for other stepper drivers with capability of providing that amount of current.
I'm a bit lost...
I have these motors 23HS5628 rated at 2.8A. Now to the board. I'm using DRV8825 drivers. If i follow your calculation it is (2.8/2)-10% =1.26v. But the boards only go max till 1,16.
Will that say i can use the boards at max vref without any problem. Or will they get very hot and break?
Your motors are a little bit over the max limit of the DRV8825 which can provide a maximum of 2.5A per coil. Theoretically you could use them at the max VRef as long as you use proper cooling (heatsink + fan). However, everything that is continually used at maximum performance tends to last shorter times. However, the drivers are so cheap that they're at least worth a try :)
what happens if you place the driver the wrong way?
and what is the current you are adjusting? is it for the speed of the stepper motor? give it more power and the stepper motor goes faster?
If you place the driver the wrong way you risk damaging either the driver or the microcontroller. Connecting things the wrong way results in rather unpredictable consequences but usually you damage/burn something. The current that is being adjusted is the current that flows into the motor coils. Each motor has a specific set of parameters for optimal operation (suppporting higher speeds and torque) and the current is one of those parameters. However the actual motor speed is defined by the frequency of the steps pin of the driver, which is controlled by the microcontroller.
why dont you post full tutorials about setting and configuring limit switches
also please put video about full arduino+cnc shield+stepper wiring and setup
Hi! That's a great suggestion for a video and I even have all the parts laying around. I might do it when I get some free time from work. Thanks!
oh thank you so much otherwise I burn my motor coils for too much current
is it okay to use a 15amper power supply for a4988?
Hi. Yes, it is perfectly ok because the A4988 will only get the amount of current set by VRef.
My motor initially worked but slowly the rotation stopped and wouldn't turn on again, do you have a solution?
I have the A4988 driver. My motors are rated at 1.5A and 1.3A, but I used the DRV8825 formula for both. Is this TOO conservative? Additionally my Rs value says "R100" so is this 0.1?
Hello Dimitrije. Yes, R100 is 0.1. I think using the DRV8825 formula is a little bit too conservative. It may even result in your motor not running smoothly (depends on the motors). Something closer to the values calculared with the A4988 formula should be better.
@@zerotoheroengineering Thank you for the information! Great video by the way!
@@dimitrijeljaljevic4234 Thank you for your kind words!
hello, if i change my voltage to the board to 24 v , do i need to change also the driver current in half or can i let the current set as 12 v
Hi. The VREF is independent of the supply voltage. You can set it and change the power supply with no problem.
@@zerotoheroengineering thank you a lot
My sensor resistors for the A4988 read "R10". I assume this means 10 milliOhms. The resistance is so small that my multimeter cannot read it. Is this value a problem? It results in Vref = 0.12V for Imax = 1.5A for the stepper motors I'm using.
Hi. You almost got it right. R10 actually means 100 miliOhms. So your VRef shoud be 1.2V (8*1.5*0.1 = 1.2V).
@@zerotoheroengineering oh wow. That’s strange notation. Thanks so much again! That helps immensely.
Would this be the same for 24v motors?
Hi. Yes, it would be exactly the same, regardless of the voltage applied to the motors
Nice video but my salvaged motors do not have any labels hahahaha
Ahah That's the hard mode :) In your case you can create an arduino sketch to continuously rotate the motor and connect everything together. Then, with everything connected and powered, slowly twist the potentiometer on the stepsticks until you get a smooth rotation of the motor. That's not the perfect and safest way, but if you're careful and know what you're doing it will work fine.
hello. for A4988 i see this formula :
current limit = vref * 2.5
vref = current / 2.5
If we want to add an i2c lcd screen module to the circuit, do we need to connect the lcd when adjusting the current limit? Because i tried connecting the lcd after i set the current limit and the motor is not working (it works if it's not connected to the lcd)
Do you have any picture or drawing of your connections? The LCD and the stepper motor driver are completely unrelated and one should not affect the other. Maybe you have some wrong connections.
@@zerotoheroengineering nevermind I figured it out, thanks🤣 because the arduino keeps sending signal to display the lcd so the motor cannot work, after i tweak the codes then it's working already, there's no need to change the current limiting potentiometer
@@leonatay248 Happy to know that you were able to solve it. Good luck on your projects :)
@@zerotoheroengineering thank you so much, you video helped a lot
i dont get any reading in my multieter for potentiometer reading ,but supply is 11v and 1.3 amps, idont know where fault lies
It's hard to guess what could be failing. The best advices I can give you are: (a) check that the supply voltage is reaching the stepper motor driver and (b) check if you get the same behaviour with a different stepper motor driver (maybe the one you used is faulty)
so my stepper motor is 1.3A; x 8 x 0.2 (0.2 is the resistance i measured) = 2.08? Seems a bit high. hmmm.....I'm definitely taking 10% from that!
Can I ask a silly question pls
Can I use Power supply with 12V 2A
Because according to the vid, I use Stepper Motor with rated current 1A, so my Vref is 0.8V. Uploading with code, my Motor does turn but it’s not rotate, just vibrate little forward then backward. I tried to change Vref a bit but it’s same as previous, except the Motor became weaker or stronger, pls help :((
Hi. Yes, you can use power supply with 12V 2A. From what you described it seems to me that your motor wires are not in the correct order. If they are not in the correct order they will turn a little bit to one side and then the other, resulting in vibration. Try changing the order of the wires. When you put the right order it will rotate as desired.
@@zerotoheroengineering thanks for your reply, and yes I do try to change the coil, and already known exacly the right coil by using Led trick. But the problem still same. Don’t know if it’s by the power supply or the Vref of the driver (a4988)
@@pipimz4734 Do you have the reference code for your motor? Are you sure that both th driver and the motor are in good condition? Do you have other motor or driver to try?
Same problem bro
Mine A4988 is showing 0 volt across potentiometer and ground even after turning potentiomenter counter clockwise. Why does it happend? i am using battery cell of 12 volt and 23 amp. Also I don think that connection of stepper is wrong.
Hi. Are you calibrating VREF with a standalone stepstick or with a stepstick mounted on a board like the ramps? Are you providing the 5V logic power supply as well? The 12V power supply is only for motor current supply. You must also provide the 5V to the logic part.
can we just stick the driver onto a breadboard without using the ramps?
Hi. Yes, you can stick it in a breadboard without using the ramps. You just have to connect the GND and VDD pins. Notice that the VDD is the logic power supply (5V), so don't connect 12V on VDD.
Thank you so much!
@@leonatay248 You're welcome! :)
Seems like A4988s have a max of 2A per coil
Yes, it can got up to 2A per coil with proper cooling. 1A per coil is the max recommended with passive cooling
I have a problem and I don't know where else to ask, but for some reason I'm getting a 12v reading off of the potentiometer
Does anyone have an idea on how to fix that?
It might be because you may have not yet connected the ramps board with the Arduino board.
@@hamzajamal5661 nah that can't be it, the first thing I did was connect the ramps and the arduino
@@ikermorell1078 try at stack overflow/exchange, you might get a solution there
@@hamzajamal5661 alright thanks I'll try
A fórmula mais adequada para Vref do drv8825 é Vref = (Imax - 30%) x ((5 x Rsense))
Hello my friend
can you help me
bingoooo
I'm glad it was useful for you :)
isn't is just A LOT easier to feed the 12V to the driver and use the multimeter to read the amps, and adjust based on that reading? see 45m40s here: ruclips.net/video/0qwrnUeSpYQ/видео.html
If you listen to what the guy on the video is saying, you have to put the multimeter in series with only one of the coils of the motor and measure the current while it is stopped (the short circuit current). It works, but there are several reasons to use the method I describe:
1 - The VRef method allows you to set the VREF without/before connecting any motor, preventing any possible damage.
2 - if you have a board with the drivers soldered on the board and motors with specific connectors on the leads it may be hard to put the multimeter in series with the motor coil.
3 - When you do your first measurement you don't know which current is set on the driver. If it is set for 2A and you use a low current motor you risk damaging the motor.
4 - If you do this on a board with multiple drivers (eg. 3D printer board) it's easier to measure 4 test points and adjust 4 screws than connecting the multimeter in series with a coil of each motor
Both methods work, but the method I describe in the video is safer and the way recommended by the manufacturers.