BEMF Capabilities

[ProjectInitiative]

I am looking at the schematic, and I don't quite see the circuitry required for back EMF sensing. Wanted to confirm this was the case. If so, would the best low speed torque management method be via IPROPI coupled with a low frequency, slow decay PWM?

[ProjectInitiative]

I also am struggling to achieve low speed torque. I read through some of the data sheets mentioned in the original #2 post, and wondering if the driver is clamping/limiting the current for the motor I have.

[CDFER]

It should only be clamped to 1A which is a lot espcially at low speed, what kind of motor, amount of load and what PWM frequency are you using?

High PWM frequency (20khz) can limit low speed torque and the min rpm.

Currently there isn't a way to directly mesure BEMF except through motor current on the MOTOR_CURRENT (GPIO5)

[ProjectInitiative]

I am testing in a Broadway limited 5 pole skewed motor, so I am trying lower frequencies and a control loop around GPIO5. It's been a while since I've done control systems, and I think I have several bugs in the firmware atm. I've been testing with 20kHz, 25 hz and 100hz. For pwm, I was attempting to let the control loop dynamically modify it based on the current load.

[CDFER]

I just looked that up and that might be a loco on the hevier side. I would get it working well before trying to get a BEMF algorithm working especially with a skewed motor because they will have a much smaller BEMF than a un-skewed motor. Also what is the MOTOR_GAIN_SEL pin set to because that also controls a secondary current limit (Should be set to HiGH-Z by default because it has no pull-ups or pull-downs but you may want to set it low to get the most current):

[ProjectInitiative]

So I had to set MOTOR_GAIN_SEL to low because I couldn't get the motor spinning at all (spun just fine on the decoder tester) I think these engines need more current. I was under the impression that setting it to low allowed for a higher current limit, when I set it to high and z high for this loco, I couldn't get it to budge which I thought was the clamped current limit. I'm going to re-read the data sheet, my understanding might be backwards.

[CDFER]

Cool sorry yes setting it to low changes to using the low resistance mosfets and should let it use up to 4A for short periods.
(edit: it should still be limited to 1A by IPROPI but using the lower resistance mosfet might also be helping)