Trinamic.
So hot right now.
Hi everyone, I’m Tom and today we’re going to take a look at the Trinamic TMC2100-based
stepper driver modules, made by Watterott electronic.
These driver modules aren’t out yet, but they already got a huge amount of attention
because they promise an absolutely silent operation of your stepper motors with a drive
mode they call stealthChop.
It also has the option of interpolating a 16 times microstepping input to 256x microstepping
output with a feature called microPlyer and has yet another # drive mode, spreadCycle,
that is closer to what traditional drivers do, but adds some intelligence to the way
it applies current to the motor.
And that’s kinda important for them, as they are not high-current drivers like the
insane Texas Instruments DRV8825.
Officially, they can only handle a permanent 1.2 amp current, which, on paper, is less
than any of the common Allegro or Texas Instruments chips.
However, they also have a 2.5 amp # peak rating - i’ll talk about how that comes into play
later on in the video.
Now, i’ll be getting into some technical details, if you are not all that confident
about what all these things mean, i’d recommend checking out both the “stepper motors”
and “steps per millimeter” videos, i explain a good bit of why and how all this works there.
So, the # one big feature this driver has is the ability to run a stepper motor at almost
zero noise - at that point, the linear bearings and the fans in your printer become the loudest
parts.
This zero-noise mode is what stealthChop is all about, the interpolated 256x microstepping
is just the icing on the cake and doesn’t really make that much of a difference.
But basically, using stealthChop effectively turns the stepper driver, which usually runs
as a constant-current driver, into a constant-voltage one, making it more similar to what a regular
brushless motor or computer fan do.
Which means that it’s not forcing the motor into position as much, but rather gently suggests
that it should maybe now move to that spot, and if it doesn’t, well the driver isn’t
going to take any extra efforts of getting it there.
So while the motor’s rotation is going to be very smooth and silent, it’s also not
going to output any decent amount of of torque, especially at acceleration and deceleration.
Which, kinda makes it pretty much useless for our 3D printers - in my case, with a relatively
heavy, non-bowden extruder, but with a fairly strong gearing on the motor, i had no chance
of printing anything at decent speeds, and the folks of DeltaMaker, who tried these drivers
with a super-lightweight bowden Delta didn’t fare much better, either - at least they got
some basic printing done, but on certain moves, the motors would still skip.
And i mean, if you look at the datasheet of these drivers, it states in multiple spots
that stealthChop is only to be used for low and medium velocities, so preferably for something
like quietly opening and closing the fan shutters on air conditioning units, but not for throwing
around heavy axes in a 3D printer.
So, now that we got / that out the way, let’s move on to the useful parts of these drivers,
and that’s basically the spreadCycle mode.
It works, essentially, in the same way as any other stepper motor driver, but it promises
some intelligent current control, for example, a reduction in current when standing still
to keep the motors and drivers cool and save some power, as well an adaptive control scheme
for quick accelerations and higher speeds.
This is where the 2.5A peak rating becomes interesting - because even if you set the
drivers to 2.5A peak, which i wouldn’t recommend, the idea is that they will rarely need to
run at that full current.
I got some basic heatsinks with these drivers, which, at least for these prototype module,
get taped to the top of the driver chips - the final version will have the entire driver
flipped so that you’ll be able to attach a heatsink to the actual thermal pad that’s
on the bottom of the driver chips and thermally available on the opposite side of the board.
So if you attach a heatsink to that side, you’ll get significantly better cooling
with the same small heatsink.
Still, i managed to get a really decent amount of grunt out of these drivers, and while i’m
pretty certain that the current output wasn’t nearly as high as with my usual Allegro A4988
drivers, the motors actually ended up having more torque.
But at the same time, they were still much quieter than the Allegro chips, even if they
weren’t exactly noiseless anymore.
I guess that’s mostly a testament to how much the Allegro’s current control loop
starts to fall apart at higher currents.
However, there was still some noise above roughly 1A RMS current, and that was due to
the fact that the driver starts to run at a lower chopper frequency the more current
it needs to supply.
Some of you might not hear it and some motors are more likely to cause it, but in my case,
there was an extremely annoying high-pitched whine coming from the motors.
The same as with the Texas Instruments drivers.
Thankfully, there is an easy way of curing that, and that is to simply supply more voltage
to the drivers.
Or, of course, to use less current, but that’s not the point here.
For testing, i simply supplied the driver from one of these super-cheap boost modules
to step up my usual 12V supply voltage to 24V and that at least changed the whining
to be far less annoying.
Of course, this means that you can’t solder in the 12V supply pin on the modules since
you’re essentially creating a second supply rail.
But, and here’s the next catch with these drivers, at least for these prototypes, you
can’t really use the default jumpers or software settings for configuring microstepping
and the different drive modes anyways.
As they only use two of the MS or MR config pins, they require three different states
to toggle through all of the available modes - pulled to ground or VCC # or, and this is
special to the Trinamic drivers, left open and unconnected.
They are still pin-compatible with the Pololu modules, and will do # something if you just
pop them in, but to take full advantage of what makes them great, i’d recommend not
soldering in the pins for the three config inputs and using jumper wire to connect them
to VCC or ground.
To use the mode i’d recommend, which is spreadCycle with an input 16 to output 256x
microstepping interpolation, you just need to solder a single wire straight across from
the first config config pin to the VCC pin and leave the other two open.
The final board will let you configure some of these modes through solder jumpers, but
many of the main boards, including the RAMPS, rely specifically on the Pololu Allegro boards
too much and even with the extra solder jumpers, still can’t configure the drivers correctly,
so it doesn’t make much sense to solder in the extra pins that pass the config signals
to the main board anyways.
As far as spare pins go, the two pins that were previously sleep and reset - which are
functions that never get used - are now a pair of diagnostics outputs.
The Trinamic drivers can try to detect when the motors skip or the driver fails for some
other reason, and while none of today’s control boards support those outputs, it would
be a great and simple way of making our printers more reliable should a board manufacturer
decide to make use of them.
The final boards will also have an extra pin that will allow the mainboard to control the
current output of the drivers.
Should you have a board that supports this, you can simply ignore the analog potentiometer
on the modules and set the current through software.
So, in conclusion, these are great little drivers if you look past the mis-marketed
stealthChop mode.
If i had to choose which current driver these most closely compete with, i’d probably
say the Texas Instruments DRV8825, since the Trinamic TMC2100 are in a completely different
league as the common Allegro drivers.
It’s not that those don’t work, but the Trinamic chips are just # better overall.
They produce more torque, run with less noise and have smarter connectivity, even if they
are currently not plug-and-play-style simple to use.
As far as pricing goes, well, there is no definitive pricing of these modules yet, but
if they end up costing about as much or a bit less than the DRV8825 boards, i’d definitely
recommend going for the Trinamic boards if you value a less noisy printer or simply want
a bit more performance than the Allegro chips can give you.
And once the control boards start using the diagnostics pins, things are really going
to get interesting.
And that’s it for today, as always, thanks for watching.
Also check out the video description, i put a few links in there to the things seen in
this video, and of course, as soon as these driver boards become available, which should
be very soon, there will be a link to them as well.
Take care everyone, see you next time!