CONSTANT AJAX disconnect errors

Dougal1957 · 13 Sept 2017, 20:10

ESP is the WiFi module that is used on the Duet
I suspect it could overload as well as being to low but i am not an expert in this and I dont know what levels I was seeing before the 710 was put into use

KeeganB · 13 Sept 2017, 20:18

Thanks Dougal1957,

I can easily move the router to test the overload theory, but I highly doubt it will change. But hey, I'm not opposed to trying, as I am certainly no expert! I have noticed a lot more wireless networks around from the neighbors lately, so I probably need to go in and make sure I am on my own channels and such anyways.

mhackney · 13 Sept 2017, 20:27

After an M999 the Duet comes up, via USB an M587 shows the network. M552 S1 just seems to hang but M122 shows connected to access point. But I'm unable to load DWC pages. IP address is correct. M552 S0 then M552 S1 will allow me to reload DWC and connect.

Seeing WiFi signal strength -79dBm when it can connect and WiFi signal strength -82 to -84 dBm when not. Could it be that sensitive?

I have a NETGEAR AC1200 WiFi Range Extender arriving tomorrow.

KeeganB · 13 Sept 2017, 20:31

It may help to know that I was having the same connectivity issues on 1.18 as I am on 1.19.2. I upgraded to 1.19.2 in an effort to resolve them. I know you said you were rock solid on 1.18, Michael, but I wasn't so maybe that can lend a clue here.

When you get the disconnects, does the Duet printer in question still show actively connected on your wireless network? Next time this happens I will ping the IP and see if it responds.

mhackney · 13 Sept 2017, 20:31

I am seeing that my Mac - which is in the same room 4' away is showing a good connection with RRSI -62dBm and 145 MBps transmit rate. But the Duet is more shielded in the base of the printer (delta) and closer to a wall so that could explain the signal drop. I'll report back when I have the AC1200 hooked up.

mhackney · 13 Sept 2017, 20:33

My router shows the Duet disconnected. Ping times out.

Jarery · 14 Sept 2017, 00:06

I'll jump in to this thread as well with same issue, I have multiple posts on this same issue in several threads

https://www.duet3d.com/forum/thread.php?id=2466#p24112

I "believe" I was not having issues on 1.18, but I only had my duet a week or so before the 1.19 upgrade came out.
I am also using a Mac as browser device, if that is an issue.

My signal strength is quite strong:
Network state is running
WiFi module is connected to access point
WiFi firmware version 1.19
WiFi MAC address 5c:cf:7f:a4:a1:64
WiFi Vcc 3.12, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 39168
WiFi IP address 192.168.2.53
WiFi signal strength -35dBm
HTTP sessions: 2 of 8
Socket states: 2 0 0 0 0 0 0 0
Responder states: HTTP(1) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)

This way we can summarize and keep it to one thread

KeeganB · 14 Sept 2017, 02:41

Well, I changed the channel for my network to a new channel just as a test, updated the machine name and password, and have been running just off of wifi for about 30 mins now.

My RSSI is -44dBm

I was missing the "P" in front of the machine name/pass in my config.g files, so that fixes the issue with the web control always showing "My Duet."

I haven't been able to print, as my G32 went crazy after the update to 1.19.2

I will continue to test.

Jarery · 14 Sept 2017, 02:57

I've run with channel as auto, channel 1, channel 6.
No difference for myself in ability to stay connected.
I also do have the "P" in front of machine name.

I've been connected for now 2 days without dropping,, As soon as I print, or sometimes calibrate I drop connection within 20 min, sometimes 2 min.

Edit:reason I have not lost connection in 2 days is because I've been busy and not done anything with the gui, nt because I've solved the issue.
I believe this dispels any lack of signal strength reasoning. Signal is strong but for some reason once commands, prints, calibration starts causing the printer to be active the wifi connection drops, as if it can't keep parallel processes going.

Edit 2: reconnecting to the laptop remotely that has the browser interface running, which ran for 2 days, and now an hour later when I reconnect it has the AJAX error and another disconnect.

dc42 · 14 Sept 2017, 06:19

To all of you who are experiencing disconnections, but only when the printer is not idle:

After doing a print, what is the MaxReps figure in the M122 report? Please note, MaxReps gets reset every time you run M122.

mhackney · 14 Sept 2017, 15:35

David, just to be clear what you are asking… when the disconnect occurs during the print do you want us to let the print complete then attempt to connect and get the M122 report or use Pronterface and do M122 while the print is running? Or something else? I just want to collect the most useful info for you.

dc42 · 14 Sept 2017, 15:54

It doesn't really matter. It's probably most useful if you run M122 shortly after the disconnection, and again at the end of the print.

Also please report your printer geometry, steps/mm and maximum travel speed.

mhackney · 14 Sept 2017, 16:09

After print completed, reconnected and M122 from DWC:

MaxReps: 411, StepErrors: 0, FreeDm: 240, MinFreeDm 120, MaxWait: 10976ms, Underruns: 0, 0

Delta, M92: 800 steps/mm M350: 64 microsteps

Max travel: X Y Z 7200

dc42 · 14 Sept 2017, 18:10

Thanks. The MaxReps is too high, so the step ISR is starving the webserver of CPU cycles. For now, I suggest you reduce either max travel speed or microstepping. When I have implemented dynamically varying microstepping, you will be able to increase them again.

mhackney · 14 Sept 2017, 19:04

is reducing microsteps to 32 enough? or do I just need to test it?

dc42 · 14 Sept 2017, 19:30

Reducing to 32 will probably be enough, but run M122 and check MaxReps again at the end of a print.

dc42 · 14 Sept 2017, 19:33

I have created a new wiki page at https://duet3d.com/wiki/WiFi_disconnections_and_AJAX_timeout_errors with suggestions for users who experience this issue.

I have it on my list to investigate the CPU starvation cause and see what can be done to reduce its impact or at least provide easier diagnosis.

mhackney · 14 Sept 2017, 19:50

Thanks David, will do on the M122.

The interesting thing is, how or even IF this would affect idle connectivity? Since changing this, I have not had a disconnect just idling in an hour, whereas I would barely stay connected for 10 minutes up until now.

dc42 · 14 Sept 2017, 20:15

No, this issue should not affect the connection when the printer is not moving, because no step interrupts will be generated. However, I've seen it once when I homed the printer with high microstepping selected, starting with the head close to the bed so that the homing move was a long one.

mhackney · 14 Sept 2017, 20:47

Odd! I am still connected - over 90 minutes - and until I made that change I've not stayed connected for more than 10 minutes on idle since upgrading to 1.19.2. And this is without homing or anything, just starting up and letting sit.