TMC 246a status bit receiving fault via TMC 428

[krkoc]

Good day,

I’m working on a product solution with your TMC 428 and TMC 246A. All the programming work is done and the stepper motor runs fine.
Now as I started to work through stall detection via readout of the TMC 428 datagram high and low word. I recognized that two of three driver modules work properly, by sending back the required ‘LD’ bits.
But one doesn’t?!? I did use the same TMC428 and stepper motor to detect this fault.

I tried almost everything to get this one running (send back status bits via TMC 428):
- different boot order
- different sequenze of switching the power supply
- (I know that’s wrong) disconnecting the one with failure and connecting one without, during operation
- and all in all let the stepper motor run, to exclude the option that the driver doesn’t run, with a continously updating monitoring of the datagramm (each ms)

Setting:
- continous refresh mode is switched on


So I can’t get it in my head why two are working and one not.

Do you have any suggestions?

Kind regards

Kristian

[TRINAMIC_BD]

I can only imagine, that you are not polling the corrent bits in the Datagram high word for the 3rd driver. Or did you use an TMC236 instead TMC246 for this one?

[krkoc]

Hello again,

At this point of programming I do all my experiences with just a single driver connected to the TMC 428 controller, so that I would expect that all the response messages would be the same.

I did my layout in this order:

1. Micro controller who does the setup work like LUT and this kind of stuff, and also serves as protocol translator for the communication between PC and TMC428.
2. The TMC428 controller who is just connected to a single driver output.
3. The TMC246A driver

The Micro controller and the TMC428 are both at one PCB, the driver at a separated one. So that the only difference between these three boards is just the IC itself.

Any further ideas?

Sincerely yours

Kristian

[TRINAMIC_BD]

You should probably first check, if you get any response at all. Is the "Always 1" bit set at the expected position (bit 8 )?
If no, disconnect the last driver's SDO line in the chain and put it to +5V. Now, TMC428 should receive all one bits for all attached drivers.
If just the StallGuard bits do not show anything, probably the motor does not deliver enough signal in the new applicatoin --> Try with a different velocity.

[krkoc]

Hi,

So, today I’ve got a little play with this driver board again and I did my tests as you said.
… just connect this board directly to the SPI channel of my micro controller and send a message to it…
My results are as follow:

- the motor still does its work (is running without any problems)
- there is no response from the driver board, even the permanent ‘1’ is missing
- I guess, there is something wrong with the output channel (SDO)

Do you have any new ideas for me?

kind regards

Kristian