Expansion 3HC M906 not working properly

fcwilt

@deckingman said in Expansion 3HC M906 not working properly:

You still haven't posted the result of sending M906 without any parameters, so we have no way of knowing whether your claim that the board is not accepting the current settings.

I don't know how to post a link to a previous post so I will just paste it here again:

I rebooted a few times using different M906 values in the config file.

After the reboot I executed M906 from the console and the values reported always matched.

I should have said cycled power instead of reboot since that is how I forced the reboot.

So the values are being accepted by the 3HC but something happens to kill the torque to the stepper.

After power on the torque always seems to be good but any reset kills the torque including the reset that is done after editing config.g and allowing the reset.

It's not just a problem with the torque. I also have a thermistor connected to the 3HC. It reads correctly after power on (in the 20s) but a reset usually screws it up and it starts reading 2000.

I haven't tested any other inputs and outputs on the 3HC yet to see if they also have issues.

It's no wonder that you are having problems with your printer.

Frederick

hackinistrator

i think wrong current setting on exp board might explain many issues people having , including deckinman .

see my post a month ago here :
https://forum.duet3d.com/post/204483

to me that issue was also too low current setting .
it seems 3.3 solves that issue (maybe due to proper delay at start up) , so maybe its worth trying .

fcwilt

@jay_s_uk said in Expansion 3HC M906 not working properly:

@fcwilt how long have you had it?
might be a lazy crystal

The 6HC since 11/2019, the 3HC since 02/2021.

Since everything seems to be good after power on but any reset causes issues how would that relate to a crystal?

Frederick

jay_s_uk

@fcwilt in can influence the start up times but it's mainly associated with older expansion boards

deckingman

@fcwilt said in Expansion 3HC M906 not working properly:

@deckingman said in Expansion 3HC M906 not working properly:

You still haven't posted the result of sending M906 without any parameters, so we have no way of knowing whether your claim that the board is not accepting the current settings.

I don't know how to post a link to a previous post so I will just paste it here again:

I rebooted a few times using different M906 values in the config file.

After the reboot I executed M906 from the console and the values reported always matched.

I should have said cycled power instead of reboot since that is how I forced the reboot.

So the values are being accepted by the 3HC but something happens to kill the torque to the stepper.

After power on the torque always seems to be good but any reset kills the torque including the reset that is done after editing config.g and allowing the reset.

It's not just a problem with the torque. I also have a thermistor connected to the 3HC. It reads correctly after power on (in the 20s) but a reset usually screws it up and it starts reading 2000.

I haven't tested any other inputs and outputs on the 3HC yet to see if they also have issues.

It's no wonder that you are having problems with your printer.

Frederick

Before you go off on a rant at me, I suggest you look at who my post was directed at which was @mauriciomartins. He hasn't confirmed what he gets when he sends M906 which is why I asked him. I know what you said.

fcwilt

@deckingman

I wasn't ranting - just making sure that you had the information you asked about.

Frederick

dc42

Startup problems with Duet 3 6HC+CAN-connected boards are sometimes caused by the main board running config.g and sending commands to the CAN-connected board before they have fully initialised. So I recommend adding command G4 S2 early in config.g and making sure that all commands in config.g that refer to devices attached to expansion board occur later in config.g.

deckingman

I'm just wondering if start up problems might be the reason why 3 of my 6 extruders motors failed over the last 18 months. Is it possible, in such a situation, that motor current might have defaulted to something too high? they were small motors and IIRC, they were rated at 800mA and I had them set to 600mA.

It was most likely a bad batch of motors so when the last one failed, I replaced all 6.

fcwilt

@dc42 said in Expansion 3HC M906 not working properly:

Startup problems with Duet 3 6HC+CAN-connected boards are sometimes caused by the main board running config.g and sending commands to the CAN-connected board before they have fully initialised. So I recommend adding command G4 S2 early in config.g and making sure that all commands in config.g that refer to devices attached to expansion board occur later in config.g.

As a first step I added a G4 S5 command (line 15) as shown below:

M111 S0         ; debug off

M550 P"MB6HC_1" ; printer name

M555 P2         ; firmware compatibility (P2 = Marlin)

M552 S1 P0.0.0.0; enable (S1) network (P0.0.0.0 = use DHCP)
M586 S1 P1 T0   ; enable (S1) FTP    (P1) Disable TLS (T0)
M586 S1 P2 T0   ; enable (S1) Telnet (P2) Disable TLS (T0)

G21             ; dimensions in mm
G90             ; absolute coordinate values for X,Y,Z,etc
M83             ; relateive coordinate values for E0,E1,etc

G4 S5           ; wait for expansion boards to initialize

Now after a reset all seems good.

The stepper has torque and the thermistor reads correctly.

Frederick

dc42

@deckingman said in Expansion 3HC M906 not working properly:

I'm just wondering if start up problems might be the reason why 3 of my 6 extruders motors failed over the last 18 months. Is it possible, in such a situation, that motor current might have defaulted to something too high? they were small motors and IIRC, they were rated at 800mA and I had them set to 600mA.

The motor current defaults to zero on all Duets, including expansion boards. The only time that a driver should supply excess current to a motor is if two mosfets in the output bridge fail short-circuit. In that case, the driver will report a short circuit but not be able to turn off either mosfet, and the driver or output mosfets will get hot.

deckingman

@dc42 said in Expansion 3HC M906 not working properly:

@deckingman said in Expansion 3HC M906 not working properly:

I'm just wondering if start up problems might be the reason why 3 of my 6 extruders motors failed over the last 18 months. Is it possible, in such a situation, that motor current might have defaulted to something too high? they were small motors and IIRC, they were rated at 800mA and I had them set to 600mA.

The motor current defaults to zero on all Duets, including expansion boards. The only time that a driver should supply excess current to a motor is if two mosfets in the output bridge fail short-circuit. In that case, the driver will report a short circuit but not be able to turn off either mosfet, and the driver or output mosfets will get hot.

Fair enough. I'll put it down to bad luck/a bad batch of motors.

fcwilt

@dc42 said in Expansion 3HC M906 not working properly:

Startup problems with Duet 3 6HC+CAN-connected boards are sometimes caused by the main board running config.g and sending commands to the CAN-connected board before they have fully initialised. So I recommend adding command G4 S2 early in config.g and making sure that all commands in config.g that refer to devices attached to expansion board occur later in config.g.

Does the 6HC have the ability to query expansion boards to see if they are fully initialized?

Frederick