Farmbot Express stalling x axis: Change to closed loop steppers

I’ve installed my extended Farmbot Express (4.5 x 2.7m) and its working but the x axis running along the wood of the garden bed is often stalling, getting stuck and missing steps.

I’ve got 2 spare NEMA 23 Closed Loop Steppers like this https://www.omc-stepperonline.com/closed-loop-stepper-kit/tp-series-1-axis-closed-loop-stepper-cnc-kit-1-2nm-169-97oz-in-nema-23-motor-and-driver.html (except mine are 1.85Nm).

Can I connect these stand alone stepper drivers to the Farmduino Express board?
I can see how I can fit them on the gantry without causing much issue.

The huge extra torque and close loop system should resolve my issues.

2 Likes

O - K :exclamation: . . versus the FarmBot kit-supplied stepper ( ~ 0.45 Nm ) should fix “everything” :slightly_smiling_face:

Can’t address your main questions as I don’t yet have a live working bot to play on :slightly_frowning_face:

1 Like

I think that the key here is how much power can the stepper drivers produce? The Farmduino uses the same, or similar, driver chips to many 3d printers, which all have a similar small stepper motor size. Although your proposed upgrade uses far more powerful stepper motors, this power has to be delivered by the stepper motor driver board, which is designed for the small stepper size on the Farmbot.
Upgrading the motors to a more powerful variety would only work if the drivers are able to provide the extra power that larger motors need.
If I was considering this, I would find out how much power the drivers on the Farmduino can produce and start from there.

The problems you are experiencing may be because your bed isn’t straight or your steppers are configured wrong.

Please share your configuration from the device settings.

Also read this Aluminum rail for the Farmbot Express XL.

2 Likes

The closed loop steppers have their own drivers that are separately powered. They don’t use the TMC 2130s on the farmduino board.

I should have read your post properly - sorry I didn’t notice the link you provided. As long as you pick up the Step, Dir and Ena signals from the existing driver sockets, this should be fine. I’ll be interested to hear how it goes if you proceed, whilst the existing steppers and drivers will work well if everything is mechanically right, there isn’t a lot of room for errors creeping into the mechanics. Stronger steppers will provide a larger “brute force” approach to issues such as misaligned rails, or debris getting mixed up with the mechanism.

1 Like

Thanks. Yes, I’ve seen this. Its clear that the Farmbot Express simply doesn’t work properly running on the wood.

I am looking into using some aluminium rails I have.

I’m also looking into using steel linear rails, which are much cheaper than the Genesis V Slot rail solution.