I tried to output 1/8 steps using seeduino, but as you can see in the photo, it’s far from a pseudo-sine wave.
I tried to output 1/8 step using seeduino XIAO, but it’s far from a pseudo sine wave as you can see in the picture.
Is anyone else in the same situation?
Are you doing the example under “Microstepping” here? Easy Driver Hook-up Guide - SparkFun Learn
How is it being powered? Share a photo of the setup/connections and describe the power arrangement in detail
Thank you for your response.
Currently, as per the attached document, I want the 1/8 step waveform in the A3967 specification, but is it possible to get it?
Please confirm.
I am having the same problem.
The waveform specified by the A3967 for the 1/8 step microcontroller is different from the output waveform, and it looks similar to the one in his diagram…
Is this a difficult driver issue to solve? :’-(
Does it look any different if you scope the output with a stepper motor attached to the easydriver?
Also, this note in the datasheet could be part of your issue.
"The mixed-decay mode is controlled by the percent fast decay voltage (VPFD). If the voltage at the PFD input is greater than 0.6VCC then slow-decay mode is selected. If the voltage on the PFD input is less than 0.21VCC then fast-decay mode is selected. Mixed decay is between these two levels. "
Thank you for your reply, I tried it right away.
The result was that a 1/8Step waveform with only the positive range was output.
The stepping motor connected was 5.2Ω.
It was certainly driving, but the output was not bipolar.
Does this mean that it is not possible to output the waveforms listed in the A3967 specifications?
I would appreciate any comments you may have.
You might need to change the decay mode at the appropriate point in the output waveform to get an output that looks like the one in the datasheet. I don’t have one of those boards to test but you should be able to duplicate what’s in the datasheet.
Even if you can’t duplicate the waveform, the board should be able to drive the motor just fine no matter what microstepping mode you choose.
Thanks for your reply.
I changed the decay mode by putting a resistor directly into R17. Could you tell me if you know how to manage the modes in a seeduinoXIAO (≒ Arduino) program?
The reason I need a bipolar waveform is because I want to use it to move an actuator.
If the actuator you’re trying to drive has a bipolar stepper motor inside, the easydriver will run it even if the waveform isn’t what you’re expecting.
Thank you for your advice, YellowDog-san.
When I connected a stepper motor, it output a bipolar waveform.
I have one question: why does it become a bipolar waveform when I connect a stepper motor?
Is it related to the change in resistance value depending on the rotation angle?
It probably has something to do with induction and how the motor coils interact with one another. You’d need to ask the chip manufacturer, they would know.
Thank you for your advice, YellowDog-san.
Today chip support send me a message about A3967.
“The A3967 monitors the phase current of each winding as a voltage across the current sense resistor Rs and determines the decay mode. This may be the reason why the output waveform you want is not obtained with your motor.”
that’s all.
thank you all,this topics done.
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