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From Pumping Station One
Java Master 2002 Coffee Roaster (view source)
Revision as of 15:20, 29 October 2022
, 15:20, 29 October 2022no edit summary
Hot air temperature range is 530-575 F on the controller. For 1-2 lbs, it should be set close to 530 F. For 2-3.5 lbs, it should be set between 540-560.
Hot air temperature range is 530-575 F on the controller. For 1-2 lbs, it should be set close to 530 F. For 2-3.5 lbs, it should be set between 540-560.
Target bean temperature can be set between 375-445 F.
Target bean temperature can be set between 370-445 F. This parameter determines the darkness of the roast.
Suggested roasting para!eters will be listed here as more data is gathered.
Suggested roasting parameters will be listed here as more data is gathered.
== List of Currently Authorized Users ==
== List of Currently Authorized Users ==
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== Technical Details ==
The roaster uses a Watlow PID controller (on the left) to control air temperature. It outputs a process value (4-20 mA), which an Avatar Instruments power controller uses to change the power to the heater via SCR phase dimming. The Avatar supports 240 V but the heater itself only can handle 208 V. This machine was designed to operate on 208 V but JavaMaster confirms it can operate on 240 V with an adjustment. Originally, JavaMaster suggested we limit the PID to 70% max output power. But that resulted in unexplained oscillations in temperature typically +/- 30 F. The Avatar includes an optional feature to limit output voltage via the V-LIM trim pot. This was adjusted so 100% on the PID corresponds to 208 V as measured by a true RMS voltmeter. Moving this back to 208 V will require re-adjustment of this trim pot.
