Stepping Up Your Stepper Drivers

[AutoWiz]

I have been playing around with and researching stepper drivers. When I first got into 3d printing one of the first upgrades I did was swapping in drv8825 drivers for the greater microstepping(1/32 vs 1/16). Then I tried the tmc2100 drivers because I love the silence of stealthchop. Sadly there is reduced holding torque in this mode. And you have to find ways to externally ground pins to enable any other mode because the 3d printer mobos are made to send power to the config pins not ground. But then I found these tmc2208 drivers. Oh man. It's like they were made just for 3d printers. the config pins use power to enable modes so you can just use the jumpers under the stepper driver to configure. I leave the jumpers in for ms1 and ms2 and remove ms3. This sets it in stealthchop2 at 1/16 microstepping with 1/256 interpolation and it is so unbelievably quiet. Well worth the money. Here is a short video from Trinamic on these stepper drivers:

https://www.youtube.com/watch?v=FvW93yCbqFE

With the tmc2100 I had to turn the print speed down a bit to stop skipped steps. These are better. And do not require any special soldering or wiring. They are plug and play. I got 9 of them for both Printalicious and the Tevo Black Widow from an ad identical to this one:

http://www.ebay.com/itm/TMC2208-V1-0...cAAOSwmZdZinKx

It is incredible what these drivers do. It is like hitting the mute button on your tv.

[spegelius]

Interesting, so these new drivers have enough torque even in StealthChop mode? I have couple of TMC2100 and they need to be in SpreadCycle mode to have enough torque, needed some soldering to get there. They are quite quiet even in SpreadCycle mode, though, so probably not going to buy the new ones just yet.

[AutoWiz]

the tmc2100 drivers can work fine in stealth chop. Most people just don't understand that they need to slow down the printers motions. The jerk is what creates the skipped steps. But don't take my word for it. Here it is from the mouth of trinamic:

https://www.youtube.com/watch?v=c3v9E1AwDBE

But the 2208 is a replacement for the 2100 and makes a few improvements to how they get configured and a new stealthchop or stealthchop2.

[curious aardvark]

so when you say quiet - do you mean you lose the r2d2 noises ?
I really like those lol

Is there any other advantage ?

[AutoWiz]

well there is the 1/256 interpolation for each of the 16 microsteps. This goes in the opposite direction of the inaccuracy brought on by the higher microstepping in the drv8825. This gives repeatable accuracy in between steps. And the interpolation makes these drivers more accurate than the a4988. They can handle more load than tmc2100 and really are just the next incremental increase or so it would seem from where I sit.

[curious aardvark]

which means what in practical terms, for idiots :-)

[Davo]

Heh. (filler text)

[AutoWiz]

which means what in practical terms, for idiots :-)

It means that the stepper driver actually has 256 steps in between each full step. but it takes in only 16 micro steps from the board. So you program marlin according to 1/16 micro stepping(just like you would configure it for a4982 or a4988 or tmc2100 drivers. And the driver takes a full step, slices it into 256 micro steps and then each step commanded by the mainboard gets counted by the driver as 16 steps. so 256 steps equates to 1 full step. And in effect with only 1/16 micro stepping you get tremendous accuracy.

Micro steps are a thing of imagination. A math. Guesswork at best. The fixed points in a stepper motor are the full steps. and each full step is an exact thing. the driver energizes one of 2 coils in the motor and it pulls the rotor to the next step. Then the driver energizes the second coil and it pulls the rotor to the next step. and by energizing the coils one after the other we can make the motor turn. toggle them the other way for reverse direction. But for microstepping we power both coils together and vary voltage to bring the rotor to a theoretical point that is in between steps. The 1/256 interpolation while only letting you have 1/16 micro stepping is a novel way to increase the accuracy of these in between step steps.

[Davo]

That's a good explanation.