122-28176 Parallax Inc, 122-28176 Datasheet - Page 227

• 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

change, an open-loop system cannot automatically compensate because there is no
feedback informing the system what the actual process variable is doing.
Challenge 6-4: Stand-Alone Control
The BASIC Stamp program and StampPlot interact to control the system. The controller
receives input from the computer interface for the settings of the ADC offset and span
based on temperature range and the amount of PWM for proper regulation of the
incubator.
If StampPlot is not running, the BASIC Stamp will cease to run as it awaits data that
never arrives. This leads to excessive expense and possible unreliability of the system.
The setting of PWM to control temperature was found by manual control. The setting
can also be hard-coded into the BS2 program to run stand-alone.
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In the initialization section of the code, set the ADC voltage variables to
appropriate levels to control the ADC. This allows monitoring of the system by
StampPlot when desired.
In the initialization section of the code, set the PWM drive variable to the
appropriate setting, found through testing, to maintain temperature in the 'yellow'
under normal conditions.
Comment out (place an apostrophe in front of) any
program that read values from StampPlot.
Save your program as StandAloneIncubator.bs2.
Disconnect from StampPlot.
Run your code.
Connect briefly with StampPlot to ensure proper temperatures are read and that
the PWM control has no effect on the BASIC Stamp (as the slider is moved, the
% PWM will still be marked at the top of the plot but should be disregarded).
Disconnect on StampPlot.
After several minutes, connect on StampPlot again to check on the control of the
incubator.
Discuss your code changes and results.
GOSUB
commands in the