Stepper current Anet A8 Plus - Robin Nano v3.1 - TMC2209

Hi,
I'v just got my Robin Nano v3.1 here with TMC2209 drivers. But I couldn't find any accurate information about the current I need for my steppers.
Contacting Anet I didn't get any answer... So maybe anyone got an idea?

My stepper drivers are TMC2209 V2.0 MKS.
I'd like to use UART mode on the Robin Nano v3.1. So do I have to setup the potentiometer on the drivers itself anymore or is the current set up in digital manner?

Edited 2 time(s). Last edit at 02/01/2022 06:14AM by cysign.

Internet says there is no such thing as a anet a9 plus

But basically you have to examine all the stepper motors for any labels for clues. Looking for a current rating

You're right...it's a typo I corrected!

I already googled for one stepper....but there are different current settings on the internet for this thing.

Can't see the z-axis labels without unmounting them. But the others are all the same:

Extruder: STEP MOTOR 42SHDC3025-24B LOT NO.200730
Y-Axis: STEP MOTOR 42SHDC3025-24B LOT NO.200905
X-Axis: STEP MOTOR 42SHDC3025-24B LOT NO.200903

They're rated 0.9A on this blog:
[caggius.wordpress.com]

Whilst on this site they're marked for 1.5A:
[www.druckzeug.de]

I found [3dprint.wiki]

Which looks like they might know what they are talking about.

so Rated Current 0.9A sounds good.

Now note this is Peak current * 0.707 for RMS current, ie what TMC's use ie a absolute max value of 636.3

Also check the value of the r-sense resistor on your stepper drivers. most are 0.11 ohms, but some are not.

Attached is a picture of one of my drivers. Looks like R7 = R110 = 0,11 Ohm would be Rs.

What do you mean by 636.3?
Multiplicationfactor between RMS current and peak current?


//edit: Ok, I see => 0,9A Peak *0,707 = 0,6363A RMS

So do I have to set the current using the potentiometer on the PCB or do I set it digitally using Uart? I've never been using uart on stepper drivers...

Edited 3 time(s). Last edit at 02/01/2022 01:46PM by cysign.

If you can enable uart, you can set it in firmware. this is the point of uart, to be a able to set all the stepper driver parameters in software/firmware

Edited 1 time(s). Last edit at 02/01/2022 05:48PM by Dust.

There'a a Marlin repo on github for the Robin Nano v3.x - so it should be possible

Quote
Dust
I found [3dprint.wiki]

Which looks like they might know what they are talking about.

so Rated Current 0.9A sounds good.

Now note this is Peak current * 0.707 for RMS current, ie what TMC's use ie a absolute max value of 636.3

Also check the value of the r-sense resistor on your stepper drivers. most are 0.11 ohms, but some are not.

Why do you say 0,9A is peak current?
Unless otherwise specified the "rated current" should be the RMS value

Most sales documents and datasheets list PEAK, as bigger numbers are better for sales. They very rarely provide RMS

The current listed are also the listed DC Voltage / Coil Resistance, ie PEAK

Edited 3 time(s). Last edit at 02/26/2025 07:26AM by Dust.