My motor "rated current" is 1.4V. I assume that this is the maximum current
The guy explains in the video how to calculate the Vref and the X_CURRENT value of Marlin
RMS current = Max current / 1.41 = 1.3 / 1.41 = 0.92 Vref = (RMS Current x 2.5) / 1.77 = 1.3 V 90% Vref = 1.17 V // to avoid maximum power in the motor X_CURRENT = 1170 mA // magic, I don't know why the guy of Teaching Tech does this convertion
Actually, I have read just now that one person says in a comment of the video:
[...] the numbers are wrong. When populating the current values in Marlin, it's asking for the RMS value in mA, not VREF. If we take the given values and take 90% of what's calculated, we'd end up with [...]
So the new calculation would be:
X_CURRENT = 90% RMS current = 0.92 * 0.90 = 0.828 A = 828 mA
I have also read in the TMC2130 datasheet:
Integrated power MOSFETs handle motor currents up to 1.2A RMS (QFN package) / 1.4A RMS (TQFP) or 2.5A short time peak current per coil.
- Is he right? Why is he converting
1.17 V => 1170 mAdirectly?
- The rated current shown in the motor datasheet is the same as the maximum current?
1.170 A < 1.2 A RMSor
0.828 A < 1.2 A RMS, the driver will not shut off, right?
- Are my calculations right?