M305 Thermistor Values for the Duet 2 WiFI on the Ender 3 Pro?



  • I'm new to 3D printing and I'm probably in a little over my head, but I like a good challenge and this has been a fun one. I recently got an Ender 3 Pro and ran it for a couple weeks to get familiar with it. Everything seemed to work fine and prints at 200 C turned out just fine. I then installed an configured a Duet 2 WiFi board with a BLTouch sensor and everything is working...for the most part. I've followed documentation, guides and recommendations from the Duet sites (mostly from this article and links contained in it: Ender 3 Pro and Duet Maestro Guide (yes, I realize I have a WiFi, and adjusted accordingly, followed the entire guide, including auto tuning of heaters)). The problem I'm running into, is that it seems to print a lot hotter than the temp I set in the slicer (using Cura). I've printed out a temp tower, and currently I set the print temp in Cura to 175 C (it's the temp that looks the best on the temp tower). Prints seem to turn out fine. However, I'm worried that somethings not configured correctly for the thermistor, since I'm printing at such a low temperature (recommended low for the Creality black filament I'm using is 195, also tried it on some red Overture filament and it was the same). Unfortunately, I don't really have a way to check the temp other than the temp gauge that's used for our furnace (that's about 15 feet away from the printer). I'm not sure how accurate it is, but the nozzle/bed report 24.7 C, and the gauge on the wall reports ~26 C. My current config is as follows:

    M305 P0 T100000 B4092 R4700
    M143 H0 S125
    M305 P1 T100000 B4092 R4700
    M143 H1 S275

    The above are the settings that were from the web configurator for the Ender 3 Pro. I have read through this forum post, and tried T98801 B4185 for the hot end and the bed, but those settings seemed to print even hotter, so I ended up going back to what I posted above. I admit, I'm not familiar with all the math that's going on to deal with these values, and I'm guessing the B value is correct (I couldn't really find that in the firmware I downloaded for the Ender 3 Pro). I'm wondering if others have this issue or if there could be something I've overlooked.

    Any help is much appreciated. Thanks!

    Board: Duet WiFi 1.02 or later (duetwifi102)
    Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 2.05.1 (2020-02-09b1)
    Duet WiFi Server Version: 1.23
    Duet Web Control 3.1.1


  • Moderator

    @McJJJ said in M305 Thermistor Values for the Duet 2 WiFI on the Ender 3 Pro?:

    M305 P0 T100000 B4092

    Try M305 P0/P1 T100000 B3950 and see if it matches more closely to the previous temp tower performance.



  • @Phaedrux said in M305 Thermistor Values for the Duet 2 WiFI on the Ender 3 Pro?:

    Try M305 P0/P1 T100000 B3950 and see if it matches more closely to the previous temp tower performance.

    @Phaedrux, thanks! That seems to work better and align with what would be acceptable temperatures.