Thursday, November 24, 2016

PID Control

A PID controller is a control loop feedback mechanism commonly used in industrial applications. – PID Controller, Wikipedia

Area under the Curve (AUC)

The idea that the area under the temperature curve could be an indicator on how much total energy the beans might have receive during the roasting process popped up already some years ago. While the rate-of-rise (RoR) of a temperature curve, calculated as the first (discrete) derivation, gives the current "speed" of the temperature increase and allows to predict the future, the area-under-the-curve (AUC) describes the past.

Monday, October 10, 2016

Die Zweite Deutsche SCAE Röstmeisterschaft 2016

The second German SCAE coffee roasting championship took place last week on 5-7 October @Probat in Emmerich. It followed very closely the protocol and style of last year's roasting championship.

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.

FZ-94 (4) – Taking Control

Now that Artisan can talk to the drive controllers, it is not only possible to read the drive speeds, but also to control the drive speeds. However, that needs some further configuration changes on the drive controllers as well as some additional setup on the Artisan side.

Friday, August 12, 2016

FZ-94 (3) – Connecting the Drives

The FZ-94 comes with two Delta VFD-L drive controllers often referred to as frequency drives. One controls the drum speed, the other the air flow via the fan speed. Both are operated manually via a dial. While Artisan can log roasts automatically by reading the three temperature values from the machine via its RS485/MODBUS connection, the drum speed and air flow, both of which have a considerable influence on the resulting roast, have to be manually marked via some user defined buttons or sliders.

Videos: Curve Controlled Roasts with FZ-94 and Artisan

See also:

The video below may be a little boring for some because I did not cut footage from it to skip any part that may be uneventful. Do slide back and forth at will to see / ignore any part you want.

Saturday, August 6, 2016

FZ-94 (2) – Pushing the Drum Heat Limit Controller

That third MaxWell MTA-48 temperature PID, all the way to the right on the front of the FZ-94, plays a dual role. Besides reporting the actual temperature of the roasting drum, it is wired to control the heaters based on the set temperature limit.

FZ-94 (1) – Bumping up MODBUS

In this first post on an improved FZ-94 setup for Artisan v1.0 we are focusing on the communication between the machine and the software. MODBUS RTU speed in Artisan prior to v1.0 was limited by an issue in an underlying library. That resulted in each request/replay pair to take at least the amount specified by the serial timeout parameter, which defaults to one second.

FZ-94 (0) – Playing with the CTE Lab Roaster

Some new features in Artisan v1.0 open up advanced possibilities to log and control the Coffee Tech Engineering's Lab Roaster  FZ-94. This series of posts describe an improved setup that supersedes the one documented in an earlier post.

Wednesday, August 3, 2016

First successful curve controlled FZ-94 roast with Artisan

(See also: my previous blog)

Roastmasters working with a PID like the Fuji PXG4 could in the past already enjoy the "autopilot" feature of Artisan, making sure the roast profile neatly coasted along the curve saved from a previous roast.

Now, Artisan has its own internal software PID and if you can link it to a device that influences your Bean Temperature (BT), you could use this option to automatically correct the live roast curve to develop along the curve you have as your current ideal.

Sunday, July 31, 2016

Coffee-Tech FZ-94 working seamlessly with Artisan

Artisan 1.0 screen with sliders for FZ-94 on the left

Recently, we received the opportunity to get an FZ-94 lab roaster and see how this roasting machine could work seamlessly with Artisan. An inspired back-and-forth between Marko Luther on the Artisan side in Germany and the R&D team of Coffee-Tech in Israël ensued and soon, the first machine was communicating fully with a newly expanded and freshly compiled version of Artisan.

Monday, March 14, 2016

Artisan v0.9.9

A number of productivity features have been added on request to this version. The ones that might be of interest for a wider audience are described below. For other more specific addition and bug fixing see the change log.

Sunday, March 13, 2016

Roast Calculus

This post is going to review the subject of roast calculus. This calculus is about change and motion. Everything is dynamic. Measurements of changes are vehicles for understanding a wide spectrum of physical processes. Knowledge of the universe comes from observations of changes and not from static measurements. We use calculi in real life every day. In a car for example, the speedometer measures a rate, the speed. The odometer integrates the speed over time, the distance, and the foot pedals control the acceleration, rate of speed.  

by Rafael Cobo


Alternatives for displaying the roast time, bean temperature (BT) and environmental temperature (ET) have been added for those, fighting with small screen sizes on their main roasting computer, but having a secondary screen available.