Hello,
I've been trying to get this kit running, but encountered an issue. From what I observed and tested the current measurements seem to be significantly incorrect.
I used an example project and implemented my own speed ramp and if I set required rotation speed to 200 rev/min, rotor ramps up and when it is approaching desired speed state machine goes into fault state. Through debugging I can see that fault transition was caused by overcurrent at phases A,B or C (seems to be random between different attempts). I modified the code to store the current values during an overcurrent event and used an oscilloscope with current probe to measure the current. When app went into fault my variables showed that current on phase C was -2.5 A while on the scope I could see only 320 mA (Overcurrent on phase A caused an overcurrent fault, it showed 6.1 A while on the scope current was never greater than 1A amplitude).See attachment fault2.png, faultcurrA.png, faultcurrC.png. On picture fault2.png yellow signal is voltage measured on current measuring comparator. Because scope probe is set to AC coupling, DC offset is not visible
I tried chaging current measurements scales in the app, but it lead to OC comparator trigerring hardware overcurrent protection. Both software and hardware protection take their current values from those comparators and I could adjust both OC thresholds, but I did not want to burn anything.
I've checked the reference manual for the power board and found that OC measurement uses voltage ref to offset current measurement so that we could measure negative currents as well. Problem is that in the manual voltage reference is 3.3/2 = 1.65V , but in my case it is 5/2 = 2.55V.
See attachment curr_offset.png
I thought I could change the jumper to switch to 3.3 ref but on my board both header pins are 5 V. Could it be that my hardware protection voltage divider is tuned for 1.65 voltage reference?
Thanks in advance!
