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

Associate II

1 ACCEPTED SOLUTION

Accepted Solutions
ST Employee

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]

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If you feel a post has answered your question, please click "Accept as Solution"
3 REPLIES 3
ST Employee

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"
Associate II

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;

Associate II

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.