No more error - MINTEMP on Ultimaker Original + AD597 controller !!! Problem is solved totally !!!

[barelko_com 2]

Hi guys,

maybe my experience will help someone.

So, I've spend a lot of time to solve temperature fluctuation and error type: MINTEMP err

I cursed AD597 - huge amount of electric noise was collected by a thermocouple, when I turned on stepper motors that was unacceptable at all, also problem will rise when you have not good power supply with big high frequency noise.

I will skip my all attempts with wrong wiring etc how its was says on many forums, so the main error in wrong datasheet and controller AD597 design itself.

The solution is simple - Instead of grounding pin (8) of chip, you must include a (pull-down) resistor, 10k-100k, between minus thermocouple pin and the ground. This greatly decreased the electric-noise-induced current picked by the thermocouple, improving your accuracy to about +/-0.1C.

Also I put 4,7mF ceramic capacitor to filter +5V and I used 0.22uF ceramic capacitor in OUT signal, that improved my accuracy to at least +/- 0.02C. A brief note, different types of capacitors do differ. For low pass filters, use ceramic!

My handdrawn pics and mods photos included!

[gr5 2,210]

Great post! Wow! Nice analysis. I will tell one of the Electrical Engineers at Ultimaker about this!

I hope they fix this in a future release of the UMO. The UMO keeps changing and getting better with silent upgrades every year.

I don't get MINTEMP on my UMO but I know many people have had issues.

The "D" term in the PID controller is very sensitive to noise/error so getting better than .1C accuracy would make the PID controller much better.

[Cohen 4]

Sounds good! Nice results!

This design was before my time, but I know we've had issues with it. That is one of the reasons we switched to a PT100 for temperature measurement in the UM2 and UMO+.

Because the UMO is no longer in production, we only have a small stock left of these boards for spare parts. Therefore it's not worth it to upgrade it I am afraid.