Other Parts Discussed in Thread: DRV8424
Hi,
I am testing right now the current regulation through the Vref voltage in a stepper moto using the DRV8424EVM evaluation board. I have the following configuration:
- 1/8 Step
- For testing, Vref is configured to give a Full scale current of around 1A.
- Current measured in AOUT1 and BOUT1 with a Shunt (2A-200mV).
If I check the following table:
If I am right when the system starts the current must be 71% of Full scale current in both coils (710 mA) and at the moment that the pulses starting at STEP pin the AOUT current must increase and the BOUT current must decrease.
If I measure only the AOUT1 current with the oscilloscope I see that the AOUT1 current goes to 71% of Full scale current but then decreases instead of increasing, doing what BOUT current should do.
If I connect a second Shunt to measure BOUT and I measure both channels at the same time:
Channel 2 (Green): Current at AOUT1
Channel 1 (Yellow): Current at BOUT1
It seems that the AOUT is working as BOUT and BOUT as AOUT. How is that possible?.
Thank you very much
Regards
Jenifer
