122-28176 Parallax Inc, 122-28176 Datasheet - Page 274

• 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

In this activity, though there is an output based on error, there exists no feedback that
would control the window blinds in an attempt to maintain the light level. But you can
imagine that based on the amount of error, and therefore the proportional output, in an
actual system, the higher the magnitude of the error, the more control action that would
be taken.
Testing Integral Evaluation ΣE∆t
In this section we will test the integral control based on error over time. Since the BASIC
Stamp does not have continuous internal timers, all times for samples and evaluations are
approximations.
Set 1
Set 2
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In the
Compare the output plot to your previous for the same amounts of error. Notice
the four-fold increase in output action taken for the same error as before.
In the code, comment out the proportional subroutines and uncomment out the
integral ones:
' GOSUB CalcProp
' GOSUB MarkProp
GOSUB CalcInteg
GOSUB MarkInteg
Download the code and close the Debug Terminal.
Set the time between samples to 4 seconds.
Set the control plot range to +/− 32,000 by clicking the "Widen" button several
times.
Increase the time of the plot to 200 seconds.
Connect on StampPlot.
Reset the plot, reset the BASIC Stamp, and slowly darken and lighten the sensor
over 30 seconds or so.
Partially shade the sensor to a light level equal to the setpoint, and hold for 10
seconds.
Allow full light to fall on the sensor for 30 seconds.
CalcProp
subroutine, multiply the Error by 4 and retest.