The TMC2209 driver cannot control the motor

Hi,

the flags say, that the driver detects an short circuit or condition or overcurrent condition. When an overcurrent is detected, the driver retries two times, before it switches off finally and raises the flag. The counter becomes reset after some time. That means, that in your application the overcurrent happens with a certain, random frequency and each few weeks results in a shutdown. 

Maybe you can find the overcurrent condition in normal motion by tracing motor currents with a scope. Is deceleration too high? Does the motor sometimes do an abrupt stop? In StealthChop, a sudden, non-smooth change of motor velocity can lead to too high coil current. 

A potential cause also could be a motor step loss, e.g. caused by changing load or manual interaction. With low resistive motors, the generative current can be higher than the driver current and thus lead to an overload.

This however, is harmless, and your software can react to it by clearing the condition (disable, clear flag, re-enable) and homing the driver again.

It could also point to an error in motion ramp generation, like a sudden motor stop for reversal rom high velocity. Check software and STEP / DIR line signal quality.

Last, it could point to static charge accumulating in the system. This can also lead to destruction of the electronics. Make sure to have mechanical parts (motor, gearing) tied to system GND.

Hope this helps.

Hi,

What was mentioned earlier actually makes sense. I’m currently testing by intentionally simulating more motor slipping to see if I can reliably reproduce the issue.

However, in practice, the behavior is not very consistent. It’s not always the case that simply power-cycling the board makes it work again. Sometimes the board has to stay powered off for an entire day before it works, and in some cases I even have to re-solder the TMC2209 to get it running again. I’m trying to understand why this might happen.

There is also another related issue: during motion, the motor occasionally starts losing steps (I saw it twice in one month). Once this slipping happens continuously, the motor cannot run properly anymore. Interestingly, after re-soldering the TMC2209, everything works normally again.

Based on these symptoms, do you think this could be caused by a PCB-related issue or is it more likely a firmware problem?

Any insights or suggestions would be greatly appreciated.
Thanks in advance!

Hi Phien,

that sounds strange. Please check your board, if all high current traces use a sufficient amount of vias (a single via might be insufficient to carry motor current). Do all boards show the same behaviour? Further, please check for any floating input pins. 

Hi,

I’ve been using this chip for a long time now, across about 10 different designs. Out of those, only 2 boards have shown this issue. The schematic is exactly the same for all of them. The failure frequency is also quite low — over the past 6 months, it has happened about 5 times in total on those 2 boards.

When the issue occurs, sometimes it can be fixed just by re-soldering the chip, or by leaving the board powered off for an entire day, after which it recovers by itself. However, it never recovers immediately.

I’ve noticed there is a TMC2226 version, which comes in a larger package. I’m currently considering switching to that part.

Besides that, I honestly didn’t expect to get a reply from someone who knows the TMC2209 this well.

Soldering of TMC2226 is easier and it can be better optically inspected. I can only imagine a floating trace, e.g. due to broken via or PCB trace having this kind of long term effect.