Chocolate tempering machine (Heater control)

Hello,

I'm new to this forum. I have decided to try and make a chocolate tempering machine like this one:

ChocoVision rev V

As you can see from the link they are really expensive machines. I have a really good idea about how I can make everything on the cheap (200 - 300 USD), but I struggle with figuring out how I want to make the control of the heating element.

I want to use this heater

Heater (danish link)

It has some really simple electronics, and can be set at 1000 W (which seems comparable with Rev V) and can run the fan without heater, which I will use for cooling the chocolate. My first idea was to use a simple solid state relay and simply turn the heater on an off, to control the temperature, but I thought it would be nice to use an Arduino and use some of the PID libraries to make the temperature control really precise, which is needed for chocolate tempering. Also using an Arduino Mega2560 with a touch screen, I could make a really nice user interface, which is a bonus.

I guess I could make the PID just turn it on an off with the solid state relay, but I thought it would make my device even more precise if I could control the power of the heater from 0 to 1000 W with the Arduino.

But I'm not completely sure how to achieve this. I've found this component:

Kemo M240 Power Control

As I read the datasheet I can use the Arduino PWM 5V signal to control the component, and the just connect the heater element trough the component, thus controlling the power of the heater. That sounds really simple I think, but not sure it would work?

The component is also rather expensive, so maybe there is another solution that is better or cheaper. I found this tutorial 220 V AC PID tutorial, but it seems more complicated than just buying the component, though it is probably cheaper (but maybe I need to put much more time into it, so in the end it is not worth the possible savings).

So hope someone can help me in the right direction. Is the Kemo M240 going to work out of the box? Are there cheaper and just as easy to use components or modules for the Arduino? Is the homemade PID AC controller a better way to go?

By the way, I'm working as a programmer and is a physicist, so I'm not afraid of programming and tingling with the electronics, but I would still like to keep it as simple as possible.

Thanks in advance for any help coming my way.

Make a system drawing (block diagram) to show what needs to happen. From that, devices and sensors that fit your purpose can be identified.

I tried to make a diagram of the process, unsure if that is what you meant (all temperatures will of cause have to be variable in my program, but it is always heat, cool, heat a tiny bit and keep at temperature). It is important in the process that the temperatures are hit pretty precise (fx. +/- 0.2 °C or something like that). To keep the temperature as precise as possible I thought power control of the heater would be nice, instead of simply turning on/off of the 1000 W heater, to avoid overshooting. Also it is not clear to me, how to change the continuous output of a PID algorithm to an on/off signal. Will clamp value of output between 0 and 1, and then round down below 0.5 and up above simply work? Will it be able to control temperature precise enough for a 1000 W heater, with the simple on/off?

There will also be stirring of the chocolate to keep the temperature even, but that is a simple on/off of a motor, and is not part of the control loop.

Just in case you decide to get it done faster, here's a PID control for a 220V solid state relay that's only $14.
https://www.aliexpress.us/item/3256803952448330.html

Yeah, thanks. I know of these, and that could be an option, but I would like to make the whole process automated and with a nice display. But I guess that is just an on/off thing it will do, so I guess I could go for the solid relay option for the Arduino as well, just unsure if the 1000 W would make it overshoot a lot, which is a no go with chocolate.

It's best done with a zero-crossing SSR, but you can apply PWM to the heater to modulate the temperature change.

If you reduce power to the heating element with PWM or phase cutting, what will happen with the parallel connected fan motor?

To do that requires the chocolate to be stirred and you snow NO stirring in the diagram.

since the fan out of the box can run with and without the heater I think I can run it independently of the heater. One of the reason I chose this heater fan. I know I will have to take the heater apart somewhat and rewire some of it, but I don't think that is an issue for me.

Agree, as I wrote under the diagram there will be stirring, but that will be controlled independently of the temperature, so that is a simple on/off control, which is easy.

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