Losing connectivity (Wifi, Paneldue, and USB)

makotosan

When I power on my Duet 2 Wifi, I can connect to it via the web interface as well as interact with it through the PanelDue. However, after a few minutes, I lose Wifi connectivity, the PanelDue doesn't interact with it and I cannot maintain a connection through USB.
My PanelDue says that it is at 0.2mm z-height, even though it's well past that.
It is still printing currently just fine, but I have no way to interact with it. This started happening recently. I am on the latest Wifi firmware version (1.23) and tried out version 2.02 and 2.03RC2 and neither fixed the issue.
Is this a hardware related issue or software? Is this a known issue, and is there a remedy?

makotosan

In case this is more helpful, here's the reported firmware version:
M115
FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 2.03RC2 ELECTRONICS: Duet WiFi 1.02 or later FIRMWARE_DATE: 2019-05-14b2

makotosan

I was able to remedy this situation by setting up a dedicated Wifi access point for the Duet using an older access point. Someone mentioned that the Duet doesn't work well with MIMO or dual band networks. The older access point that I set up, an EnGenius ECB350 AP, is just a 2.4 GHz network with no MIMO and it seems to be working well.

WarriorMe

Have you started to see this issue AFTER doing a firmware update?
I'm having the same connectivity issue, but i am fairly certain that it was caused by a firmware update to version 2.02. I've never seen a similar connectivity loss before, and after the update it now happens fairly often. Note though that i've also updated the PanelDue Firmware, so i guess it's not entirely impossible that is causing the issue instead.

I'll run the next few prints with the wifi module disabled, if your theory is right i'd assume that'll prevent the connection loss.

dc42

My Asus router is MIMO and dual band, and Duet WiFi boards work well with it (only in the 2.4GHz band of course). But there may be some particular routers that Duets don't work well with.

makotosan

@dc42 Thanks for the response. I also have the "Smart Connect" feature which assigns devices to the 2.4 GHz or 5 GHz network based on rules, and the AI Mesh feature with multiple ASUS routers. I am wondering if it's due to the Smart Connect or the mesh features.

dc42

Does Smart Connect know when a client can do 2.4GHz but not 5GHz?

makotosan

@dc42 Not 100% sure. I know that within the rules, you can apply the rule to "AC" clients only (802.11ac). Although I do have other devices that are only 2.4 GHz on the same network that maintain a connection.
From what I have read, the ASUS router has a "bounce detect" that will stop trying to steer a client if they cannot connect to the other band in a certain period of time.

I will try out restricting the steering to 5 GHz to only 802.11ac clients and put the Duet back on the network to see what will happen.

makotosan

I was also getting errors too frequently (every 2 seconds or so) about the Wifi module.

See this video:
https://youtu.be/1MD_5E8soJQ

dc42

We initially had the WiFi lose the connection frequently when we moved a printer to 3D Meetup Sweden. Changing the WiFi channel solved the problem.

When you do get a WiFi connection, what is the reported signal strength in the M122 report?

makotosan

@dc42 It is currently connected and reports a strength of -34dBm:
- WiFi -
Network state is running
WiFi module is connected to access point
Failed messages: pending 0, notready 0, noresp 0
WiFi firmware version 1.23
WiFi MAC address xx:xx:xx:xx:xx:xx
WiFi Vcc 3.35, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 24112
WiFi IP address 10.10.0.239
WiFi signal strength -34dBm, reconnections 0, sleep mode modem
Socket states: 0 0 0 0 0 0 0 0

dc42

Interesting, because -34dBm is very strong. It's still worth while trying a different channel setting on your router.