Work in progress, Vax potting pot..

[Claus H]

Working on an Arduino controller for a deep fryer for vax potting... It's properly total
overkill but been working on it for a while...

Quick peek



Been working with a PID controller, but settled for a simple controller it's stable within 3 degrees Celsius

[salvarsan]

Been working with a PID controller, but settled for a simple controller it's stable within 3 degrees Celsius

In turning a Crock Pot into a sous vide cooker, I found out a few things.
You can get a nice temperature controller, K thermocouple, and SSR relay kit for $30-50. eBay and Amazon sell them both bundled and separately.

The more expensive ($28-35) controllers will run directly off mains AC, handle a variety of temperature sensors, and the displayed temperature limit is essentially that of the sensor you choose. I am partial to the JLD612/TET612 for those reasons and because it handles cooling and heating systems both.

The cheap PID controllers (~$10 = REX-C100) have a firmware-limited temperature range 0-999.9C, only work with one sensor type, and must be powered from DC only. There are better REX controllers but you don't want them. Just get a good brand from the start.

While Platinum wire sensors (namely, a Pt100 RTD) are the most accurate, they are godawful slow, need at least 5 minutes to equilibrate. The one below reads 32.0 degrees Fahrenheit and it's only a class B. As temperature references go, ice water is the holy trinity of good+fast+cheap.



K thermocouples have a good response time usually well under 60 seconds at a minor cost of +/- 1C accuracy, so good+fast+cheap is still yours.

Warning on SSRs: The market is flooded with semi-counterfeit solid state relays (SSR) from FOTEK. If it costs less than $20, it's probably a 12 amp one relabeled as 25 amps and may not survive running your 1200 watt crock pot. The $15 controller+sensor+SSR bundles on eBay are guaranteed to have the REX-C100 controller and a relabeled SSR. Vendors LightObject and ColdFusionX cost more but sell a reliable bundle.

[mozz]

I think by the time you spend all the money and time involved, you can just buy the hide glue pot for ~ $100 or used for less.

[Claus H]

Yes indeed but where is the fun in that I Have tried a glue pot with a thermostat but it's never truly 65 or 70 degrees C
The setup is really stable now +-1 degree has a little overshoot problem at first heat up from cold. But running all day here with different pickups in and out of it, it's very stable Money I spend on it well I paid 100 Danish kroner or the deep fryer, 50 kr on the SSR 100kr on the Arduino..
Still under 50 bucks US

[Claus H]

In turning a Crock Pot into a sous vide cooker, I found out a few things.
You can get a nice temperature controller, K thermocouple, and SSR relay kit for $30-50. eBay and Amazon sell them both bundled and separately.

The more expensive ($28-35) controllers will run directly off mains AC, handle a variety of temperature sensors, and the displayed temperature limit is essentially that of the sensor you choose. I am partial to the JLD612/TET612 for those reasons and because it handles cooling and heating systems both.

The cheap PID controllers (~$10 = REX-C100) have a firmware-limited temperature range 0-999.9C, only work with one sensor type, and must be powered from DC only. There are better REX controllers but you don't want them. Just get a good brand from the start.

While Platinum wire sensors (namely, a Pt100 RTD) are the most accurate, they are godawful slow, need at least 5 minutes to equilibrate. The one below reads 32.0 degrees Fahrenheit and it's only a class B. As temperature references go, ice water is the holy trinity of good+fast+cheap.

[ATTACH=CONFIG]41608[/ATTACH]

K thermocouples have a good response time usually well under 60 seconds at a minor cost of +/- 1C accuracy, so good+fast+cheap is still yours.

Warning on SSRs: The market is flooded with semi-counterfeit solid state relays (SSR) from FOTEK. If it costs less than $20, it's probably a 12 amp one relabeled as 25 amps and may not survive running your 1200 watt crock pot. The $15 controller+sensor+SSR bundles on eBay are guaranteed to have the REX-C100 controller and a relabeled SSR. Vendors LightObject and ColdFusionX cost more but sell a reliable bundle.

Thanks I tried a PID controller but it overshot like crazy I probably did not have the right constants, I programmed a real simple PI controller with the Arduino, ha' calling it a PI controller! it's more like a real slow PWM controller but works very well, have done tests all day, after the initial overshot from melting all the vax, it stable at 65 degrees, well plus/minus 1.. So I am real happy..

[salvarsan]

Thanks I tried a PID controller but it overshot like crazy I probably did not have the right constants, I programmed a real simple PI controller with the Arduino, ha' calling it a PI controller! it's more like a real slow PWM controller but works very well, have done tests all day, after the initial overshot from melting all the vax, it stable at 65 degrees, well plus/minus 1.. So I am real happy..

Congratulations.

These days, I follow the Principle of Maximum Laziness and would have looked at the Arduino PID sketches for ideas.

Searching on "arduino PID autotune" is instructive.