Communication between two Duet boards

mokka

I want to send commands between a Duet 2 WiFi and a Duet 3 mini 5+ board, to for example, pause or change the speed on the other board.

Is this possible by simply connecting the RX and TX from the PanelDue ports and send the command with M118 P5?

dc42

@mokka that sounds feasible. I suggest you connect 1K resistors in series with the Tx/Rx wires between the boards, to protect the board better if only one of them is powered up.

benecito

@mokka
Any hints on how to configure both duets for the communication to work?
Just tried but did not (yet) figure out how to do it, so it actually works.

dc42

@benecito I assume you are running RRF3. You will have to configure the UART port on both boards to run in raw mode at a suitable baud rate, using M575.

benecito

@dc42 Just configured both with

M575 P1 S2 B57600

and tried to send

M118 P5 S"Test"
or
M118 P2 S"Test"

but nothing arrives on the second board.
And yes both running 3.3.

dc42

@benecito how do you know that the other board received no data? If it received "Test" then it isn't going to do much except maybe report the current tool number.

If you are sure it is not receiving anything, check that you have TxD (or OUT) on one board connected to RxD (or IN) on the other board, and vice versa, and you have the grounds of both connectors connected together.

benecito

@dc42 probably found the mistake - we connected TxD with TxD and RxD with RxD.
Will try again as soon as I find a chance.
Thanks for the quick help!

benecito

@dc42 all right - one step further...

configured both with

M575 P1 S2 B57600

and sent for example

M118 P2 S"G1 X100"

The printer moves but after that it seems to be a little "stuck". I.e. DWC does always report "busy" and does not report the right position. It also does not respond to a M114 set trough DWC.

dc42

@benecito as you only need to send data one way I suggest you connect just the TxD pin of the sending Duet to RxD on the receiving Duet, so that the responses from the receiving Duet are not interpreted as commands from the sender.

benecito

@dc42 I‘ll need to think that through as I believe we’ll need to send things both ways.
If we don‘t I‘ll try it!
It’s there another (easy / easier) way to make two duets communicate?