@tlfong01 For the move current we need to have a value of 0-2.5VDC (Section 1.4 Driver Manual). This value is chosen by PWM in a digital pin from Teensy 4.1. This value has nothing to do with Accelstepper. As this library only deals with position, velocity and acceleration.

Also by looking at the manual, we see there is another pin for stand-by current. I use this pin with PWM to quantify the holding torque; Howver, today I measured that by setting it to PWM = 255, the holding torque only goes to 6 Nm not the 9 Nm that is in the motor Datasheet.

@tlfong01 My main problem is to find a way to know the Torque at a defined speed, by measuring the current.

@tlfong01 Regarding this, in the main question page I wrote that we would have 1.41 * 9.5 = 13.4 A. And for the torque constant we have (Holding Torque)/current = 9/13.4 = 0.67.

Let me read the manual again.

Now the relevant pictures.

@Amirmkr There is slight problem here: Have you used a scope to display the Teensy digital pin with PWM 255 signal, to make sure it is an analogue DC signal?

@Amirmkr Well, you might have mistunderstood the adjective "standby" in the standby current. Are you sure it is related to the "holding" of the holding torque?

@Amirmkr As I pointed out earlier, you might have mixed up the concepts with (1) DC motor and stepper motor, (2) torque and torque constant.

@Amirmkr We need to first make sure that we agree on the definition of torque and torque constant, which I pointed out earlier, are very different things. The below Singapore Uni EE&CE prof's YT gives a good explanation/clarification:

Talk is cheap, let us calculate:

You can find below more motor specs for you to calculate motor torque.

You might also like to watch another prof lecturing how to find motor constants Kt and Kb.