I too smoked a driver set up on a bread board.
5v confirmed to logic pins, DIR not connected.
24dcconnected to motor supply and ground. Logic and drive grounds not tied together.
Previous poster also saw same smoke part of chip ( top left or bottom right) but letters on chip are gone.
I had 2.5a motor coils connected and thought over current and over temp would shut device down. No heat sink attached.
What should I check for without using spare driver as new fuse?
Voltages rechecked ok without board in place.
I too smoked a driver set up on a bread board.
I am sorry to hear about your DRV8825. What did you have the current limit set to? What is the rated voltage of the stepper motor you are using? Did you put an electrolytic capacitor across VMOT and GND as shown in the minimal wiring diagram on the product page? The driver does have overtemperature and overcurrent protection, but unless you had a capacitor across VMOT and GND, I suspect it was an LC voltage spike that damaged the board. If you are not familiar with what that is, you can learn more about it under the Power connections section of the driver’s product page.
By the way, the grounds are internally connected on this board, so it is not correct to say they are not tied together.
I have a 100uf lytic on vm.
I am set up nearly the same as diagram, but I am using a signal generator (5v p-p) to drive the pwm line.
I mention the grounds because there is a post about different dc sources having delta v between grounds. Sounds like that is not possible.
Is there a power up sequence that matters? If 12vdc vm is connected and no 5vdc is not or vica versa, could that be an issue.
I’ll try with no motor and see if new board is ok. I have the nema 23 motor @ 2.7a peak that you sell, sorry forgot voltage.
Did you set a current limit on that board? If so, what was it set to? Could you double check that you are getting an output of 0-5V from your signal generator?
It sounds like you might have the #1478 or #1474 stepper motor. In general, this driver is underpowered for those stepper motors. You might still be able to use the DRV8825 to control that motor if you limit the current to within what the driver can handle, but it would not be able to handle enough current to get the rated torque from the motor.
It should not matter which order you apply logic and motor voltage to the stepper motor driver.
Can you also provide a link to the post you are referring to that talks about “different dc sources having delta v between grounds”?
I searched the archives and could find the post. It might have been for a different driver, but in essence the concluded that there was something like .5v between grounds of different dc supplies plugged into different branch circuits.
The SG is putting out 5.0 v (scope) but I am limited to about 750 pps before the motor stops spinning and resonates. I had the current set to -0.5 v at the current sense eyelet, but then cranked full tilt which did not seem to help. The board was warm but not hot! I have a 12vdc 5A motor PS.
I do have the 1778 and missed the 2.3A limit for the board. If I short the current sense resistors, can I get to 2.5A? It is not perfect but should be better than using a 1473 2.0 A class motor? At least I think so.
So basically the same setup did not smoke the second board, but I am no struggling with max RPM. Should I try a high voltage for motor?
What the highest holding torque motor you have that pairs well with 8825?
The plot thickens.
I put in a smaller nema 17 p/n# 1200 and it basically has the same stall behavior. I reduced max current to 1.2A via Vref and using the same Frequency Generator (HP).
The motors goes into a resonance like behavior at around 900hz. The bigger nema 23 also hit the same wall and both stall at anything frequency above this value. It cannot be the same characteristics for both motors?
The n17 hits another one at around 275hz, but recovers below that. It works fine down at even 1hz. The bigger motor stalled below around the same point (sort of ignored at the time) and would not move the rotor below the stall point.
I am using a 15vdc ps that can tune between 11.5-17vdc and I have tried within that range …no go. The FG has phasing and offset adjustments that allow for tuning the pulse waveform as well.
Any suggestions on how to test these drivers with better success? I am attempting a mini cnc and thought 8825 would fit the bill.
Jon, I found the thread on the ac branch circuit causing dc offset. It is not clear if connecting grounds would have helped.
I am not entirely sure I know what you mean when you say you want to “short the current sense resistors”, but 1.5A is the most this carrier can handle without overheating. Changing the current sense resistors will not change that.
The speeds you are getting seem a little low; do you have anything connected to the output shaft of your stepper motors? Using a motor supply with a higher voltage than your current power supply should help your stepper motor achieve a higher stepping speed. The posts in this thread by kevin and Ben should also help you increase the speed of your stepper motor.
The forum post you linked to was for a specific scenario where someone had two power supplies connected to two different sources that were not grounded together, so I do not think that is the same thing that caused your first board to be damaged.
By the way, the highest torque stepper motor that we currently carry that is compatible with the DRV8825 is this stepper motor.