CNC pendant not working on new motherboard
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Hi! Yesterday I replaced my 6HC motherboard because I wanted the higher voltage of the 1.02 revision (I had 1.01A hardware before). I simply transferred all the config files and plugged the new board in, while also replacing the power supply (48v instead of 24v).
Almost everything worked perfectly right away, but for some reason the CNC jog pendant is now completely unusable. Only one in maybe 20 "clicks" on the joq wheel actually triggers motion, but since it does sometimes trigger motion I can also conclude that it partly works (when it does move the direction and step size is correct). It's as if the serial port has bad connection, but I've checked and double checked the connectors and cables and I can find nothing wrong. It also worked perfectly before changing the board so I'm not expecting to find any hardware faults in the pendant or the wiring. If it was a bad connection I would also expect the behavior to change if I wiggle the cable and connectors while rotating the jog wheel, but I can find no such correlation.
The pendant is the one described here: [https://docs.duet3d.com/User_manual/Connecting_hardware/IO_CNC_Pendant](link url)
Has anything change regarding the serial interface from 1.01a to the current board? Has the 5V pin on the port been been downgraded such that it can no longer feed the microcontroller in the pendant? Or has there been a software update that could affect the serial communication?
I desperately need this to work so I'm seeking advice on where to start looking for a solution. Is there another serial port I could use for testing purposes? (I am currently using IO_0 as described in the pendant-docs). Should I try replacing the resistors of level-changing voltage divider in the pendant to lower values so they drive the data line harder? Does it truly need the voltage divider or would a 5V serial signal work? Grateful for any guidance I can get!
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Have you tried testing with the 24v psu?
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@crap said in CNC pendant not working on new motherboard:
Does it truly need the voltage divider or would a 5V serial signal work?
If you are referring to the voltage divider at the output of the pendant that feeds the Duet, that is needed when connecting it to a Duet 2 but not when connecting it to a Duet 3.
Older versions of the pendant firmware appended a checksum to the data sent to the Duet. Newer versions append a CRC instead.
Is the new main board running the same firmware versions that the old one was?
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@Phaedrux I have not, since everything else works it seems unlikely that this would be the problem. But if nothing else solves this problem I can certainly try other power supplies and see if my 48V supply causes interference.
@dc42 It sounds like I should try removing the voltage divider then to see it that helps. I built my pendant february 2022, when comparing to github this seems to be the latest firmware for the pendant.
The firmware of the mainboard has changed. Previously I had 3.4.5 and now I have version 3.5.4.Looking at the change log the only changes that mention serial port is the following line:
"[Duet 3 MB6HC] [Duet 3 Mini] A PanelDue or other device using the same protocol attached to the second serial port did not work"
So there is another serial port? If I get desperate, how do I configure this port and where is the connector? (Edit: It's on IO_1, yes? Finally found it in the docs. Same config-code just IO_1 instead of IO_0 I guess)Looking at the hardware revision I see that a separate connector has been added for paneldue. So I gather there is a slight chance that this has affected the performance of the serial interface, with more/longer traces being added. I still connect to the old IO_0 port. It gives me some hope that simply removing the voltage divider could solve the problem. And also that there is another connector I can try, in the unlikely event that the circuit board connector or the traces are the problem.
I'm sorry for asking so many questions before trying what has already been suggested. My machine is quite far from where I live so I don't have access to it every day. When I do have access I want to understand which options I have so I have a good change of solving the problem.
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@crap you may want to check and/or re-crimp the connector at the Duet end of the cable, and make sure the pins are fully inserted. Also check that the soldering of the connector on the Duet looks good.
