Cura 3.4.1 will not connect to Ender 3 via USB

[MikeUSNRet]

Cura 3.4.1 will not connect to Creality Ender 3 via USB cable after installing firmware TH3D Unified U1.R1.9B or even TH3D Unified U1.R2.T1. was working prior using the default version of firmware that ships on the Ender 3. Incompatibilty with firmware and Cura?

Application Version
Cura 3.4.1

Platform
Windows 10 64 bit

Printer
Creality Ender 3

Steps to Reproduce
Connecting USB cable between PC and Printer

Actual Results
message of Printer Not Connected In Cura under Printers => Manage Printers

Expected results
Printer should connect to PC and be recognized by Cura so that a 3D print can be done

Additional Information
none

[ChrisTerBeke]

We can't really test with 3rd party machines, so it's really up to the community to have a look at this. Cura supports any USB printer that follows the RepRap/Marlin G-code protocol, so if your firmware doesn't follow that it could cause issues.

[MikeUSNRet]

Thanks. Thought that this would be a good place to start since it worked before flashing a new version of marlin firmware to the printer and other 3rd party programs do connect to the printer via USB. was on the thought process that this was an incompatability issue with Cura and Marlin 1.1.9.

[ChrisTerBeke]

It would help if you can attach some logs (cura.log and maybe some communication logs from the USB port). That would help people here to find the problem.

[JohnEdwa]

I have an Ender 3 currently running TH3D U1.R1.9b and a laptop with Win 7 64bit which is able to successfully connect to Cura, and I've printed multiple objects with it as well, so I can at least say it's not a problem with the firmware and Cura being incompatible with each other. It could be a Win 10 issue, but it's more likely that there is something wrong with your system specifically.

[Ollowitsch]

I had exactly the same problem with a CR-10 after updatig to new Marlin-version and posted my solution also in the ultimaker community

The problem:

Cura 3.4.1 (actually it's plugin "USBPrinting") is sending gcode "M105" (request temperature) at different baudrates to the serial port. It expects at least 3 successfull response lines containing the string "ok T:" - but new Marlin is only sending 1 line matching this string - containing all temps (i.e. "ok T:27.03 /0.00 B:26.91 /0.00 @:0 B@:0\n")

The solution:

Change file C:\Program Files\Ultimaker Cura 3.4\plugins\USBPrinting\AutoDetectBaudJob.py (or whereever your Cura Plugin-dir is located) line 63 from:

if successful_responses >= 3:

...to:

if successful_responses >= 1:

...and restart Cura, which will now find the correct baudrate (propably 115200) and enable the serial communication

[wjohnsaunders]

There is a comment in AutoDetectBaudJob.py that says the following:
Ensure that we are not talking to the boot loader. 1.5 seconds seems to be the magic number

It seems Marlin 1.1.9 on the Ender 3 is happier with a 5 second delay. I also removed all baud rates, except 115200, from the list all_baud_rates. As they are not used and only makes a connection failure worse.

It seems having an Arduino bootloader resident on the printer causes Marlin to reset each time the com port is opened. I have also tested with with Putty with no serial handshaking enabled.

[cds333]

Confirmed that changing AutoDetectBaudJob.py lines:

def run(self):
wait_response_timeouts = [3, 15, 30]

TO:

def run(self):
wait_response_timeouts = [5, 15, 30]

Fixed the problem for me

[sam-ward]

I just wanted to add that I was having the same problem with my Ender 3 in Cura 3.6, but updating the wait_response_timeouts as above fixed it for me.

[tcarlisle2012]

The changes from cds333 fixed this for me too. The weird thing is it was working initially and just stopped.

[fluxkompensatorausderzukunft]

Change file C:\Program Files\Ultimaker Cura 3.4\plugins\USBPrinting\AutoDetectBaudJob.py (or whereever your Cura Plugin-dir is located) line 63 from:

if successful_responses >= 3:

...to:

if successful_responses >= 1:

...and restart Cura, which will now find the correct baudrate (propably 115200) and enable the serial communication

This fixed it for me an my Anet A6 - thanks a lot!

[Lijcraft]

I'm new at 3d printing and I cant change it, when I hit save it says something about my access being limited or denied or something, when I try to change the autodetectbaudjob.py file. Am i missing something?

Windows 10
cura 3.6

[Lijcraft]

I'm new at 3d printing and I cant change it, when I hit save it says something about my access being limited or denied or something, when I try to change the autodetectbaudjob.py file. Am i missing something?

Windows 10
cura 3.6

Also, im using notepad to edit it.

[tcarlisle2012]

You have to have admin privileges to change files under C:\Program
Files\Ultimaker Cura 3.4

The default permissions on a windows system does not allow normal users to
write to the program binaries paths, and that is a good practice actually
as it helps minimize damage if you get bitten by something malicious.
Please don't change this. Instead, either log in as the admin, or run
notepad elevated as admin. You can do this by typing "notepad" in the
windows search bar, and when notepad pops up don't left click it, and
instead right-click it and select "Open as Administrator".

Of course, you need to know an admin account and password to do this. If
you cannot, then whoever installed Cura on the system in the first place
will have to help you out.

On Wed, Jan 2, 2019 at 10:22 AM Lijcraft [e-mail] wrote:

I'm new at 3d printing and I cant change it, when I hit save it says
something about my access being limited or denied or something, when I try
to change the autodetectbaudjob.py file. Am i missing something?

Windows 10
cura 3.6

Also, im using notepad to edit it.

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[tcarlisle2012]

There is only one change to make, in that one file: See instructions
above, find line 63 and make the change as described, then save the file.
It wouldn't be a bad idea to open the file again and make sure the change
was saved.

You might find notepad++ a little easier to work with, and you won't have
to worry about things like line endings, etc.

If you did the change, and verified it saved, and have completely shut down
cura and restarted, then this fix just doesn't happen to solve it for you.
But I would reboot just to be sure.

On Wed, Jan 2, 2019 at 10:43 AM Lijcraft [e-mail] wrote:

You have to have admin privileges to change files under C:\Program
Files\Ultimaker Cura 3.4

The default permissions on a windows system does not allow normal users to
write to the program binaries paths, and that is a good practice actually
as it helps minimize damage if you get bitten by something malicious.
Please don't change this. Instead, either log in as the admin, or run
notepad elevated as admin. You can do this by typing "notepad" in the
windows search bar, and when notepad pops up don't left click it, and
instead right-click it and select "Open as Administrator".

Of course, you need to know an admin account and password to do this. If
you cannot, then whoever installed Cura on the system in the first place
will have to help you out.

I did this, now do I change one at a time or both, (Sorry if this is a
stupid question)

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[Nheters]

Hi, I'm using cura 3.6, Win10 and i have a creality ender 3, and i have the same exact behavior, where the printer doesnt connect to the Notebook, and Cura does not recognize it.

[Ghostkeeper]

I think increasing the first response time-out from 3 to 5 seconds shouldn't be a problem. It'll increase the detection time by 2 seconds for some printers though.

[nallath]

The number of sucesfull_responses needed has already been changed to 1 (instead of the old 3), so I don't think we need to change the timeout.

[Ghostkeeper]

So if Ollowitsch and Fluxkompensatorausderzukunft are correct it should be fixed in version 4.0 then.

[b1naryVap0r]

Confirmed that changing AutoDetectBaudJob.py lines:

def run(self):
wait_response_timeouts = [3, 15, 30]

TO:

def run(self):
wait_response_timeouts = [5, 15, 30]

Fixed the problem for me

a few things:
First - cura is great, it is good of ultimaker to provide cura even though i cant afford their printers. This is good for the comunity and builds their brand which is cool. in the future i will own one of their printers

its cool that this program is made in python. love python.

problem i had:

ender 3 pro wasnt connecting to printer on version 3.6 on ender 3 pro- after flashing to TH3D_UFW_U1.R2.10d ::

i took these 2 fixes from below --

in filepath where cura is installed adjust: AutoDetectBaudJob.py

change:--
def run(self):
wait_response_timeouts = [3, 15, 30]

TO:

def run(self):
wait_response_timeouts = [5, 15, 30]

& &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

if successful_responses >= 3:

...to:

if successful_responses >= 1:

then restarted Cura which fixed the problem.

[Ghostkeeper]

It's a bit dangerous to change that last bit though. If the output happens to be a valid decimal number then we connect to it. There's a reason why it asks for 3 successful responses. We SHOULD be able to expect that the printer responds in the same way.

[b1naryVap0r]

confirmed that this problem still exists, with cura 4.0, reinstalled to use creawesome mod and had to alter the autodetectbaudjob.py so my ender 3 pro would be recognized / detected by cura. everything else went fine with the mod but the printer wasnt being detected - only an option to save to file. i reinstalled without using the mod, then tried cura 4.1 beta and the issue still happened, then i reinstalled cura 3.6 and remembered that this was a thing i had to do to allow communication between ender 3 and cura over usb.

just confimed after doing the same fix that i mentioned above and installing the creawesome mod on cura 4.0 for my ender 3 pro to print over usb that cura can see the printer.

sidenote - im being verbose / pedantic above so people can hopefully find this if they have the same problem, im comfortable with python and familiar with windows 10 cura and the ender 3 pro by now, but maybe someone else isnt and this can help.