Rapido 1 Reading Lower Than Expected Temperature
I have a rapido 1. i selected the thermistor in the screenshot. It is reading around 1C when at room temperature. Bed is reading around 16C.
22 Replies
do I have the right thermistor value?
I am rebuilding someone else's project so I have no history on this hotend. i'm trying to figure out whether this has a junk thermistor.
try Pt-1000
If you start heating the hotend with a hair dryer or heatgun, does the reported temp go up or down?
Yeah in the screenshot that I posted I turned on the hotend heater with a set point of 220c briefly and it responded
Just seems like the value is off
Try setting a different 104NT thermistor. If it was supposed to be a pt1000 the numbers would be way farther off
Yeah I tried the standard 104nt thermistor and it was a similar reading
Doing a pt1000 caused a adc out of range error
The only other thing I can think of is that the thermistor had been spliced with another set of wires and the connection might not be great
oof, yeah. Check those wires
just to circle back since im by the printer again... this is what i get with another 104t thermistor:
so roughly the same. I'll dive into the wiring today
otherwise i might just shove a different hotend into it and call it good
does the thermistor read correctly when you heat the hotend up? It might just be inaccurate at room temps
Temperature does move in the right direction when heating it up but I dont have a thermistor to compare agains to generate a comparison for error at this time
I ended up swapping out the hotend and will work on it another time. running short on time to get this working this weekend
@TheTik so following back up on this… the new hotend had the same issue so it was not hotend related. I checked mellows documentation of klipper for the sht42 that I am using and it looks like they have a 2200 ohm pull-up resistor for the thermistor and the generated ratos configuration leaves the default klipper pull-up resistor set to 4700 ohm
New hotend with pull-up resistor not set in klipper and whatever ratos generated for the toolhead:
New hotend with pull-up set to 2200 like mellows config:
Looks much better. I guess the uhf rapido and wiring that I was using was ok
Thats a relief! I haven't had to mess with pullup resistors, sorry that it took a second hotend to figure it out. Learning experience!
All good. I think the autogenerated config for ratos needs to add this for the sht42
@miklschmidt see above, this is the TL;DR
Also, here’s the link to mellows klipper config recommendations so that you don’t have to go hunt for where that screenshot is from
Fly SHT-42 klipper configuration | Mellow Products Documentation
Sample configuration files for the Fly SHT-42
@Jeb Bush Thanks for the heads up! Fixed 🙂