Power profiling
Posted: Tue 17 Mar, 2020 1:59 pm
Power profiling is now available in a beta version of the firmware. This is a basic implementation for evaluation by early beta testers.
The firmware version containing the power profiling is 7.4.4.1092. https://drive.google.com/open?id=15jC8a ... M99T-ccOit
The way it works is this: in a zone, disable PID control and enable power profiling by setting the multipliers to zero. That is, set zone multiplier Kp and zone multiplier Kd both to 0. This will turn off PID control and activate power profiling for the zone. In power profiling the zone boost specifies the percent change in power during the zone. So if the boost is zero, the power will remain unchanged during the zone. But if the boost is 5.0 the power will increase steadily (linearly) to add 5% during the zone. If the boost is -5.0 the power will decrease by 5% during the zone. Once the end of the zone is reached normal PID control resumes.
Power profiling can be used to smooth out the power curve (black line) during specific parts of the roast. Run a roast with no zones and identify any zones where you want to straighten the power curve. Read off the power at the start of the zone, and the power at the end of the zone. Convert this into a percent difference. For example, if the power at the start of the zone is 1075 W and at the end of the zone is 1123 W, the difference is a gain of 48 W. As a percent this is 48/1075*100 = 4.465%. Enter 4.465 as the zone boost. If it starts at 1075 W the power will steadily increase from 1075 to 1123 during the zone. If it starts at some other value, which it might due to variation in temperature, humidity, air pressure, etc, then it works off that other value. For example, if the roaster enters the zone with a power of 1065 W, then the change will be +4.465% of 1065 which is +47.6 W and the end value will be 1112.6 W.
You will need to start a power profiling zone at a point where the roast is behaving nicely - following the profile curve and without significant wiggles in the power curve - otherwise there will be too much variation in the starting power.
I will post an example as a further post on this thread.
The firmware version containing the power profiling is 7.4.4.1092. https://drive.google.com/open?id=15jC8a ... M99T-ccOit
The way it works is this: in a zone, disable PID control and enable power profiling by setting the multipliers to zero. That is, set zone multiplier Kp and zone multiplier Kd both to 0. This will turn off PID control and activate power profiling for the zone. In power profiling the zone boost specifies the percent change in power during the zone. So if the boost is zero, the power will remain unchanged during the zone. But if the boost is 5.0 the power will increase steadily (linearly) to add 5% during the zone. If the boost is -5.0 the power will decrease by 5% during the zone. Once the end of the zone is reached normal PID control resumes.
Power profiling can be used to smooth out the power curve (black line) during specific parts of the roast. Run a roast with no zones and identify any zones where you want to straighten the power curve. Read off the power at the start of the zone, and the power at the end of the zone. Convert this into a percent difference. For example, if the power at the start of the zone is 1075 W and at the end of the zone is 1123 W, the difference is a gain of 48 W. As a percent this is 48/1075*100 = 4.465%. Enter 4.465 as the zone boost. If it starts at 1075 W the power will steadily increase from 1075 to 1123 during the zone. If it starts at some other value, which it might due to variation in temperature, humidity, air pressure, etc, then it works off that other value. For example, if the roaster enters the zone with a power of 1065 W, then the change will be +4.465% of 1065 which is +47.6 W and the end value will be 1112.6 W.
You will need to start a power profiling zone at a point where the roast is behaving nicely - following the profile curve and without significant wiggles in the power curve - otherwise there will be too much variation in the starting power.
I will post an example as a further post on this thread.