EvergreenBuzzBuzz wrote:So how will you control the gas with it. I thought this needs an electronic signal? I'm not the engineer type. Thanks.
First of all, I just started using Artisan this month - I was using Roastlogger with the Hottop. Second, I've only used a Phidget to read the thermocouple on a Scace device. In other words, I have no idea what I am doing ... but this is how I think it should work. I definitely do stand to be corrected.
The Burkert assembly is an electronically-controlled valve. The valve takes a bunch of different control inputs, but consider the 5 volt input:
- I send 0 volts to the valve - it is closed.
- I send 5 volts to the valve - it is fully open (100%)
- I send 2.5 volts to the valve - it is half-open (50%)
- I send 1v, the valve is open 20%, etc.
I see three phases to using the Burkert:
Phase 1. Use a 5v power supply (or batteries, or the 5v line in USB
) and a potentiometer and send a variable voltage to the Burkert. This results in a fancy electronic equivalent to a needle valve. Phase 2. Read the voltages from Step 1 with a Phidget VINT hub port. A VINT hub port can be configured to read a 0-5v input. For example, if I rotate the potentiometer half-way, then 2.5 v will go to Burkert and Artisan will also be told via Phidget VINT port that 2.5v has been sent to the Burkert. Now Artisan will be able to log all the manual changes made to the gas during a roast.
ETA: When I drew up the wiring diagram, phase 2 no longer made any sense. Now there is a DPDT switch to go between Phase 1 and Phase 3; the idea being Phase 3 will be roasting with Artisan, and Phase 1 will be roasting without the computer.
Phase 3. Replace Phase 1 and instead use Artisan to send a voltage between 0-5v to the Burkert. To do this Artisan has to be connected to a Voltage output Phidget. (ETA: I originally ordered the 12-bit one, but switched to the 16-bit version "just in case.") Then a slider/potentiometer (software or hardware) inside Artisan/Phidgets could adjust the gas flow. (Step 2 still does the same thing, but now within Artisan/Phidgets.)
With Phase 3 in place, in a producion scenario:
Step 0. Follow a standard morning startup procedure for your roaster
Step 1. Follow a standard warm-up/charge procedure for consistent starting conditions for each and every roast.
Step 2. Dial in your production roast for a particular coffee using manual gas adjustments (and fix your drum rpm and airflow to be Rao-esque
) Now you have the gas adjustments for your dialed-in production roast recorded in Artisan.
Step 3. go back to Step 1, but now instead of step 2, have Artisan replicate your production roast gas adjustments. You can still over-ride what is happening.
Result: Most consistent coffee. It won't be perfect as environmental conditions change, etc., but when you want to "follow the recipe ..."
More can be done - my roaster is relatively old and I can also use the Burkert to turn off the gas if a probe in the cyclone reads too high, etc.