122-28176 Parallax Inc, 122-28176 Datasheet - Page 272

• 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

Page 262 · Process Control
Figure 8-8 Proportional Only Evaluation of Light Level
Figure 8-8 is a sample of the plot. Note that data is sampled and plotted much more often
than error is calculated and total output is calculated and plotted. Time between samples
is approximate. At each sample time, the error is calculated, and the proportional amount
is plotted on the bottom plot. This program and macro have been designed so that the
error is the actual value minus the setpoint. The greater the error, the greater the output
value being plotted. In this case, output is proportional to the error.
Note that with slow sampling, the output is only a rough approximation of the actual
curve. The rapid changes in signal are barely noticeable in the output. As the sampling
rate increases, the output matches the error much closer.