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Issue
99, October 1998
X-Y Graphing Data
Logger
by
Alberto Ricci Bitti
Start
• Machine
Muscle
• Using
Componentware
• Low-Power
Guys
• Flash
Risc Glue
• The Graphic
Engine
• Casio
Protocol
• Main
Code
• Inside
The Box
• Setting
up the Casio
• First
Graph
• Modeling
The Data
• Broader
Vision
• Software,
References & Sources
SETTING
UP THE CASIO
While operating, the analog
interface box is stuck to the bottom of the calculator,
below the LCD, with TESA removable biadhesive strips.
This arrangement gives the calculator a stable and comfortable
slope, and it leaves the input connector in a handy place,
free from obstacles.
To reveal the micro jack
socket, remove the rubber cover that comes with the calculator.
If the jack is left unconnected or the unit is powered
off, a Com error message is displayed.
You don’t need any particular
programming skill to use the acquisition unit. One instruction
does it all.
Issuing Receive(X) directly
(Recv softkey in the PRGM I/O menu) displays the value
read from channel x. You can manipulate the x
variable like any other ordinary variable, exactly the
same way you would if you entered it manually. Value is
expressed in millivolts, and ranges from 0 to 4095.
Receive(X) is usually issued
under program control, as in Listing 1. But, I like to
manipulate graphs manually. It’s an instructive,
highly interactive way.
Nevertheless, every keystroke
can be replaced by a matching keyword to be issued under
program control. From the programming standpoint, complex
tasks (e.g., displaying a whole graph or computing a fourth-order
regression) count as only a single instruction.
You can specify other variable
names instead of x. Each variable selects a different
input. Variables supported are x, y, v,
w, z, s, t, and u.
Other names are seen as aliases and won’t cause errors.
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