Here you can see exactly where I've disabled pressure advance.

What's the lowest jerk you'd recommend to go with that doesn't cause issues with pressure advance?

@dc42
Hmm, S3D it is indeed, that I've used to slice it up.

And I've been tackling some ringing issues today and have drastically lowered the jerk values, this model now is printing at 120 value only.

Your comment answers something that I'm observing, PA is disabled, value 0, beside retractions the gear should be moving uniformly forward while extruding - but it's not, it does have moments of speeding up and slowing down, so what you've just said about S3D seems to be at play in here.

@dc42

Good evening sir!

Hehe by having a seizure I didn't mean anything erroneous on the side of Duet or pressure advance - I'd say it was doing exactly what it was supposed to, adjusting the pressure of extrusion according to speed and turns/corners, it was just doing it at a frequency I wasn't expecting, it hardly stopped, I have a small gear shaped knob placed on the shaft for decoration and to see retractions better and it was in constant back and forth motion, paired with the sound it makes. Hence the 'seizure' reference

From what I'd assume after lurking on forums and browsing previous posts and threads, I didn't think that S0.18 was a particularly high value, especially for a bowden with a tube that's over 60cm long.

It's an ungeared extruder feeding directly into the ptfe tube (Anycubic Kossel Linear Plus), current settings M566 E1800, M203 E1800 , M201 E1000.

Not sure what happened there to be honest, when it was tracing the rock base of this statue (3 outlines) it would regulate the pressure on every turn, change of direction or corner, but whether it's the hardware not keeping up or just jitter induced by so many adjustments, the bottom layers are all messy and misaligned, I'll post a picture soon, 4% left.

Geez I haven't posted in a long long time, connected my Duet to new delta printer, since my previous printer which housed it got disassembled, but speaking of pressure advance calibration - are there types of prints where it shouldn't be used?

I've spent last 2 day testing pressure advance, settings of jerk/acceleration etc, got to the point where a cube would print ok, but other shapes had issues. It's a Bowden tube, 65cm-ish, quite long, after temperature calibration of the PLA I'm using, I've found the sweet spot for retraction and S value of 0.18 gave me best edges.

Now, I have used Marlin K factor calibration tool as my basis ( http://marlinfw.org/tools/lin_advance/k-factor.html ), modified it to suit Duet, removed what I didn't need etc, came up with a code to test the best S value this way - and it's S 0.65 where the line is most uniform right across.

Printing geometric shapes like cubes, polygons etc looks much worse than with lower value, thick seams, bit rounded corners etc, now to make it even stranger, I'm printing a twisted tower model as I'm writing this, which is an "organic" shape, not just technical straight shapes - started it off with S value of 0.18 but the quality was shocking, extruder was having a seizure, each layer looked inconsistent compared to the previous one etc... after 10mm I've disabled it - model from there on looks perfect.

Is it not recommended to use PA for organic shapes? Sorry if it's something that was discussed to death, haven't visited this forum for a good year by now.

Here's the gcode I've used to test S value: 0_1539501893621_sfactor0.5.gcode

After a lot of testing and moving things around, I have to say that you're right after all, it must be the signal. While signal dB values change, and I can maintain the connection for quite some time - even seemed fixed at some point - while uploading new config via web interface I've noticed something very telling.

In the batch of text files being uploaded, some would pass some would fail - retry - different batch would pass and different fail, and so on…

Got it going now but resigned myself to running it via usb.

Thank you for your time mate, you can close this thread

Hmm, tried same process again, erased everything, started from scratch with new release of 1.21, connection lasts about 2 seconds, followed by:

"A communication error was reported, so the current session has been terminated. Please check your board and try to connect again."

While it lasts, I can check tabs, so getting:

Firmware Name: RepRapFirmware for Duet WiFi and Duet Ethernet
Firmware Electronics: Duet WiFi 1.02 or later
Firmware Version: 1.21RC2 (2018-02-15 build 2)
WiFi Server Version: 1.21RC2
Web Interface Version: 1.20

Nope, same story there.

"A communication error was reported, so the current session has been terminated. Please check your board and try to connect again."

Moved it closer and closer, signal isn't the issue here.

Hmm, I'll try moving it.

The printer has been in same location from the start, never lost a connection due to network issue before my firmware update woes.. I'll post an update

In the brief moment that connection is established I've checked the Settings tab in web interface, this is telling:

Firmware Name: n/a
Firmware Version: n/a
Web Interface Version: 1.20

Hmm, changed things again after having a walk to vent off hehe, used different SD card, flashed things in order, briefly had a glimmer of hope! It connected… but within seconds died again with:

A communication error was reported, so the current session has been terminated. Please check your board and try to connect again

Starting to really get on my nerves…

M122 dump:
SENDING:M122
=== Diagnostics ===
Used output buffers: 1 of 32 (1 max)
=== Platform ===
RepRapFirmware for Duet WiFi version 1.21RC1 running on Duet WiFi 1.02 or later
Board ID: 08DDM-9FAM2-LW4SD-6J9F6-3SJ6N-1LZRY
Static ram used: 15448
Dynamic ram used: 99784
Recycled dynamic ram: 3552
Stack ram used: 3568 current, 4496 maximum
Never used ram: 7792
Last reset 00:01:08 ago, cause: power up
Last software reset details not available
Error status: 1
[ERROR] Error status: 1

Free file entries: 10
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 0.0ms
MCU temperature: min 43.1, current 45.8, max 46.2
Supply voltage: min 23.7, current 24.1, max 24.3, under voltage events: 0, over voltage events: 0
Driver 0: standstill, SG min/max not available
Driver 1: standstill, SG min/max not available
Driver 2: standstill, SG min/max not available
Driver 3: standstill, SG min/max not available
Driver 4: standstill, SG min/max not available
Date/time: 1970-01-01 00:00:00
Slowest main loop (seconds): 0.099134; fastest: 0.000043
=== Move ===
MaxReps: 0, StepErrors: 0, LaErrors: 0, FreeDm: 240, MinFreeDm 240, MaxWait: 0ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.000 0.000 0.000 0.000 0.000
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
=== GCodes ===
Segments left: 0
Stack records: 1 allocated, 0 in use
Movement lock held by null
http is idle in state(s) 0
telnet is idle in state(s) 0
file is idle in state(s) 0
serial is ready with "M122" in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
=== Network ===
Network state is running
WiFi module is connected to access point
Failed messages: pending 0, notready 0, noresp 0
WiFi firmware version 1.21RC1
WiFi MAC address 60:01:94:34:3b:6a
WiFi Vcc 3.35, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 17448
WiFi IP address 192.168.1.22
WiFi signal strength -63dBm, reconnections 0, sleep mode modem
HTTP sessions: 0 of 8
Socket states: 0 0 0 0 0 0 0 0
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)