What is the simplest way to implement a IBT-2 BTS7960 motor controller

[damien]

Hi, apologies for the noob question: I've followed your instructions (thanks Xavier, Sean and everyone else who has contributed! ) with this motor controller and finally managed to get tiny pilot to drive my motor forwards or in reverse. The only thing is that I don't have a 1k potentiometer, so I just connected L_IS and R_IS to ground via a 680 ohm resistor which seems to work. Can anyone tell me what the resistance here is controlling, (motor noise pitch? Or something more critical?) and if the 680 ohms seems like a reasonable value? Or would a (lower?) value be better?

Thanks,

Manu

Hello,

Sorry for the late reply. Good to hear that you have started to implement Pypilot.

Regarding IBT-2 and L_IS&R_IS, these outputs are mirroring the current delivered by power stages of the two BTS7960 (Il=Is*Kilis with Kilis=[3000,14000] centered on 8500) . These outputs deliver a current and not a potential (voltage) hence the need for a resistor on the output to get a potential that can be handled by the arduino analog inputs. The reasonning behind the 200ohm+1k potentiometer mentionned is the relative large dispersion of the multiplier Kilis that has to be used to obtain the value of the current which means that calibration will be required. Such calibration can be implemented either in hard (using the 1K potentiometer) or in soft (modification of the code). I choose for simplification and possibility to swap between IBT-2 modules to stay with a hard calibration.
It is worth mentionning that these outputs deliver a signal modulated at PWM frequency. The pilot code is not designed to sync the analog reading with the operation of the FET bridges which means that values obtained by the ADC will be subject to caution. The code implement a simple averaging filter which takes care of some of this part but it may make sense to implement a low passs RC filter on the L_IS&R_IS output for further accuracy.


I would advise to look at the BTS7960 datasheet (https://www.digikey.com/htmldatasheets/p...s7960.html) to get a better understanding of how these drivers operate. This may help for future aspects of the implementation of this module for your pilot.

Best,

Xavier.