122-28176 Parallax Inc, 122-28176 Datasheet - Page 304

• Manufacturer Part Number: 122-28176
• Description: GUIDE STUDENT PROCESS CONTROL
• Manufacturer: Parallax Inc

Specifications of 122-28176

• Accessory Type: Manual
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

ACTIVITY #6: PROPORTIONAL-DERIVATIVE CONTROL
Parts required:
Same as Activity #1
Derivative control responds to a CHANGE in the error. The fundamental premise
determining derivative drive assumes that the present rate of change in the error signal
will continue into the future unless action is taken. Derivative drive, when properly tuned,
allows a system to rapidly respond to sudden changes and react accordingly. It can also
help damp the system to limit oscillations, and drive to limit the effects of short
disturbances.
To achieve the best plot response, we will work around the stable temperature for 50%
bias drive. Due to dealing with error over time, the smaller the resolution of our
temperature, the better, so the upper and lower temperatures will be set accordingly.
Run #1
Run #2
√
√
√
√
Co
%Drive
Connect and plot. Adjust your settings to the following:
Upper Temp:
Lower Temp:
Setpoint:
Band (+/−):
Time:
Kp:
Ki:
Kd
%Bias:
Allow temperature to stabilize.
Introduce a disturbance and monitor the resulting action.
Set Kd to 1.0, or another under-damped response that provides multiple
oscillations before stabilizing.
PID
= B + (K
TOTAL
= %Drive
P
E) + (∆E/∆t)
50% Bias Temperature + 10 (e.g. 100+ 10 = 110 °F)
50% Bias Temperature (e.g. 100 °F)
50% Bias Temperature − 10 (e.g. 100 − 10 = 90 °F)
2
1
1
0.000
0
50
BIAS
+ %Drive
PROP
+ %Drive
DERIV