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NP_it
Associate II
May 18, 2022
Solved

How to convert s16A current measurements to Nm. Which current value should i consider and how do i convert it.

  • May 18, 2022
  • 2 replies
  • 2191 views

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Best answer by Cristiana SCARAMEL

Hello @NP​,

the torque-current relationship of a motor is defined by the motor Torque Constant (Kt).

Kt = T (torque) / I (armature current) [Nm/A]

I hope this post can help you; if so, consider to mark it as best answer by clicking the label "Select as Best".

2 replies

Cristiana SCARAMEL
Technical Moderator
May 26, 2022

Hello @NP​,

the torque-current relationship of a motor is defined by the motor Torque Constant (Kt).

Kt = T (torque) / I (armature current) [Nm/A]

I hope this post can help you; if so, consider to mark it as best answer by clicking the label "Select as Best".

"If you feel a post has answered your question, please click ""Accept as Solution"""
LSong.11
Associate
July 26, 2023

Hi Cristiana, does it represent that the STMotor Pilot read Torque value (unit s16A), equal to current (A) * 65536?

As in the source code mentioned:

/* Set the backup value of hTargetFinal. */

      wCurrentReference = ((int32_t)pHandle->TargetFinal) * 65536;

LSong.11
Associate
July 28, 2023

@Cristiana SCARAMEL 

On speed_torq_ctrl.c there's an explanation STC_ExecRamp(), 

Current(digit) = [Current(Amp) * 65536 * Rshunt * Aop]  /  Vdd micro

looks like Current(digit) is 16 bit, shall s16A change to Volt(digit)? 

Could you help advise? Thanks.