L6482: Right value of R sense, for 3A stepper motors?

[val_ltd]

Posted on August 15, 2017 at 11:49

Hello,

I am using 'L6482H discovery board' design example for L6482 chip, for making my own pcb board, using the same mosfets, etc.

At this moment, my board runs really well with

2A

stepper motors and 80 mili-ohm R sense resistors. Both commands, Move (DIR, N_STEP) and Run (DIR, SPD),  run very well.

But when I use Run (DIR, SPD) command with

3A

stepper motors, stepper motors almost do not have any torque, and it is easy to block the axis. Only at very low speed they have some  torque.

I understand I have to change my R sense values

, but I am not sure the way of calculating this value for 3A stepper motors.

Please, what is the way of calculating the right value of R sense?

Thanks in advance,

Valentin

#l6482h #l6482 #r-sense

[Enrico Poli]

Posted on August 24, 2017 at 15:34

Hello,

No need to change the sense resistor value. You can increase the motor current through the TVAL_xxx registers.

Example:

Target current 2 A --> TVAL_xxx = 2 A x 80 mOhm = 160 mV

Target current 3 A --> TVAL_xxx = 3 A x 80 mOhm = 24

0 mV

[val_ltd]

Posted on September 02, 2017 at 10:54

Thank you so much,

I have just tested it, and the result was right.

I miss a document that explains these practical concepts, to help us to decide the configuration values.