X-NUCLEO-IHM03A1: link between the TVAL values of the Powerstep01 registers and the voltage across the shunt resistors ?

[LHerm.1]

Hello everybody, I have a question I can't solve. I use the X-NUCLEO-IHM03A1. My question is : wath is the link between the TVAL values in the register of the Powerstep01 (see figure) and the voltage accross the shunt resistor of the board (100 m ohms). As you can see, the value register set the peak reference voltage for the currrent mode regulation. But, if i take for example 117 mV as peak reference voltage for the holding torque, and if i measure the voltage accross the shunt resistor, it is way below this value (it is 3,6 mV) so i don't understand the link between these two value ...

Thank a lot for your Help !

[Laurent Ca...]

The question has been moved from the "STM32 Motor Control" section to the "Motor Control Hardware" section (the question is not about the STM32 MC SDK). 

Best regards

[Cristiana SCARAMEL]

Hi @LHerm.1​,

I confirm that the TVAL_X value set the peak reference voltage for the current control algorithm.

The integrated comparator compares the shunt resistor voltage with the internal reference generated using the peak value, which is proportional to the output current amplitude, and the microstepping code.

To better understand what happens in your application could you share:

• the powerSTEP01 registers configuration
• a scope waveform of shunt voltage

For more details on powerSTEP01 peak current control you can refer to the application notes AN4158.

[Cristiana SCARAMEL]

Hi @LHerm.1​,

were you able to allay your doubts?

Could you share your progress?