The FrogPad
A forum to get help or talk about Roastmaster…or anything else coffee.

Using Roastmaster with a Diedrich IR24  (Read 74 times)


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Hi, I'm new to the forum so I apologize if this is going in the wrong place.

The company I roast with owns a Diedrich IR24. It's an older model ('80s I think?) and all we have is the first generation Siemens Simatic Panel. After describing the benefits that Roastmaster could offer for our development and workflow the owner of our company gave us permission to get RM up and running on our system. Now the question is "how?".

In one sense the ThermaQ blue seems like the simplest option, but then again it would require adding an additional probe (especially since our machine has a K type probe and ThermaQ uses J). I assume that going this route would require drilling into the machine. If there is another way to do this please let me know.

The other primary option I see is Phidgets, which seems like a better long-term solution (since it would also set us up for other software if we desired, like Artisan or even Cropster). My concern is that it looks incredibly complicated to get set up. Other questions:
-Would we be able to somehow "tap in" to our existing K-type thermocouple, or get one with two outputs (not sure what the technical term is)? If not then Phidgets has the same problem that ThermaQ does—the need to drill into the roaster.
-I read somewhere on the forums that Diedrichs already had Phidgets installed... Did I misunderstand this?
-I also notice that our thermocouple has two wires running from it... Is that normal, or does that possibly indicate that it already has two outputs? If so I'll have to look into what the other one is being used for if anything.

I basically need some direction and recommendations for getting this set up. Thanks in advance!

Danny Hall

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Most folks use this forum for just tech support, so there's not the typical community traffic. Any members with more info...feel free to jump in.

No - you cannot safely "split" or "tap" thermocouple lines. The voltage they carry is extremely small, and the extra impedance would cause the temps to be inaccurate. Since factory thermocouples are utilized in safety functions, you want to avoid that at all costs.

But…that appears to be a dual tip thermocouple. One set of leads should be wired to the roaster electronics. The other set may be already wired to a Phidgets Temperature Sensor (from a previous owner maybe). See if you can trace those wires and find the temperature sensor - either a 1 port or 4 port (pics attached). If so, the temp sensor may be enclosed in a clear acrylic case, with an open port for a USB cable.

If that's the case, Roastmaster can talk to the Phidget Temperature Sensor, but since there is no USB port in iOS, you need a WiFi "host" to send the signals wirelessly. The Phidget SBC3 is a good choice.

If you're unsure, I'd give Diedrich a call and ask for clarification. There's a good chance that one set of leads would be free for data logging - regardless of the hardware installed. So, if there's no Phidgets Temperature Sensor already installed, you may still be able to use that probe without drilling a new one.

Also - you have it backwards - the ThermaQ Blue only supports K types (not J). So, if the second set of leads is free, and the probe is a K type, you could opt for that for direct Bluetooth connection.

Keep me posted, and let me know if you have other questions in the mean time.



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Awesome. That's a lot of really helpful information!

I don't know why I had it in my head that ThermaQ was J... I could have sworn I saw that somewhere, but now I definitely see it says K on their site. Very cool. I'm going to try to find where that lead goes in the morning... Thanks again for your help!