Sunday, August 14, 2016

More Alarms

Support for alarms has been around for quite a while and is in heavy use by some. More recently I got asked how to define an alarm that should be triggered 30s after the FCs (First Crack start) event.

With the existing alarm system of Artisan this is was not possible. Alarms could be triggered based on time and/or temperatures, but "time" was always taken w.r.t. the start of the roast.

With Artisan v1.0, a new "From" clause named "If Alarm" is available that interprets the specified time span since the cascaded alarm specified under "If Alarm" has been triggered.

In Artisan alarms can be cascaded into alarm chains. One alarm can block the execution of another alarm. If an alarm links to another alarm under "If Alarm" by its number, it will not trigger until that other alarm was triggered. Similarly, under "But Not" one can link to another alarm to prevent the actual alarm to be triggered after the other was triggered.

All that sounds complex, but the alarm chain feature together with this new "From" clause allows for alarms triggered after a specified time span after an event.


Let's go through a simple example: 30s after the BT reached 160C, the fan slider should be set to 40%. We define a first alarm that is triggered once BT rises above 160C after DRY.

Note that the "Time" is kept at 0:00. That means that this alarm is only considering the temperature condition. Easy, but in this case the alarm triggers immediately at BT=160C, not 30s after that.

Now let's make use of that new "If Alarm" feature to have the fan set to 40% after our first alarm was triggered. We add a second alarm, with "If Alarm" set to 1. That guards our new alarm such that it can only be triggered after the first alarm was triggered. Additionally, we set the "From" restriction to "If Alarm" and the time to 0:30. With this, the time condition (30sec) of our second alarm is taken relative to the moment the alarm of the number specified by the "If Alarm" (here 1) is fired.

The post 10 degrees above FCs discusses an alarm to be triggered once the bean temperature increased by 10 degrees after first crack start using an If Alarm rule that triggers on a relative temperature criteria.

Frans over at Kostverlorenvaart just published a more advanced example using this new alarm feature to actively help your roasting and Rick published a tutorial video on alarms on YouTube.