Duet WiFi: Configuring Steppers on a Prusa-style (TMC 2660)

I've never used *anything* Trinamic before, and I can't figure out how to configure the steppers. I'm running a Prusa-style printer. Two Z steppers, one X and one Y. All motors are 1.8 degree.

The Z axis of all things is giving me the most problems. I've set the current for Z to 1200ma. It's an 8mm pitch leadscrew, holding about 500mm of V-slot Aluminum 2020, and about 300g of extruder. Shouldn't be too much for the motors to handle, right? However, the left motor, connected to ZA, is overheating while the one connected to ZB is only mildly hot. Also, when in motion, it's really easy for me to stop one of the motors with my hand, yet at idle (idle current set to 40%) it's about as powerful as I'd expect from a TI or Polulu driver. It's also ridiculously noisy both at standby and at in motion (though they were dead quiet with no load)

Z axis runs 400 steps/mm, max 900mm/min (15mm/s), other axis 53.3 steps/mm, max 9000 mm/min (150 mm/s)

Is there a way to change idle current per driver? The Y axis is really easy for me to move by hand at idle, but the Z axis is fine at idle.

Why is my Z axis so noisy, yet so weak when in motion? I thought stallguard was supposed to prevent that. Same for Y axis at idle.

If one of your Z motors is overheating while the other one is much cooler, that suggests to me that either they are different types, or that one of them has a short in one of the windings, or you have a short to ground. Please check the labels on the motors to see what types they are, and measure the resistances of both phases of both motors if you have a multimeter. Also check for no continuity to ground. A short to ground would also explain the noise. Check there is nothing conductive below the Duet that the motor terminals could short against.

The percentage idle current can't be set per motor at present.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for your help, David.

The motors seem to be about the same temperature now. I've checked each motor to make sure that the wires terminate correctly, and the windings don't seem to be shorting to each other if that's what you meant (sorry, not experienced with electronics at all) I made sure that there was nothing conductive under the duet, and nothing seems to be touching the connectors or wires. They're the same motor. Here's a YT video with the sound.

Multimeter is on the 200 setting.

Left motor connected to ZA via a 4-wire extension (about the length of the printer, which is 500mm wide). Measured from the end of the extension: Blue-Red reads 45.9; Green-Black reads 46.3
Measured directly from the motor wires, Blue-Read reads 38.4; Green-Black reads 38.6.

Right motor connected to ZB directly. No extension. Blue-Red reads 39.5; Green-Black reads 39.2

I may not be able to help you but I would like to see your configuration files as I have a Prusa also. I have to Duet but I haven't got the files figured out just yet.

I've attached my config.

Thanks for the configuration file.

M350 X16 Y16 Z32 E32 I1 ; Set 16x microstepping

The "Z32" might need set to 16? Also, do your Z screws spin freely, as in not bound or too tight?

Quote
kenblu24
The motors seem to be about the same temperature now. I've checked each motor to make sure that the wires terminate correctly, and the windings don't seem to be shorting to each other if that's what you meant (sorry, not experienced with electronics at all) I made sure that there was nothing conductive under the duet, and nothing seems to be touching the connectors or wires. They're the same motor. Here's a YT video with the sound.

The problem is that those motors are not a good choice for a 3D printer. You won't ever get smooth movement at high speeds using them, although you will get better results if you use 24V power instead of 12V. I suggest you plan to replace them. Instead of 12V 0.4A motors, you should use motors rated at something like 3V 1.8A.

The best you can do with those motors is:

1. Wire the two Z motors in parallel and connect them both to ZA. Put the jumpers back in ZB.

2. Set the Z motor current to about 650 or 750mA and the other motor currents to 350mA. The actual motor current will be the value you requested rounded down to a multiple of 101mA.

HTH David

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Sorry, I forgot to mention that I'm using a 24v power supply.

I've switched out the Z motors to these 2A motors. They're quite a lot quieter now, though not as quiet as the other drives. Running a million times cooler though. Completely forgot to check the current rating, I assumed they were all 2A.

Can I still use the 0.4A motors for a bowden extruder, or are they basically useless with the standard tmc2660 drivers?

Thanks so much for your help!

With a 24V supply, your 0.4A motor should be OK for the extruder, although the available retraction speed may be limited. You can estimate the speed at which torque will drop off using the formulae at [duet3d.com].

Edited 1 time(s). Last edit at 10/15/2016 01:22PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].