LPL Topics
Analog Output Control (D/A)
23-74
Using the LI-6400
23
An Example
Figure 23-35 contains a little program that lets you control the light source by
pressing the up and down arrow keys.
The program turns on the flow control board first, since that must be on to
control the lamp. Then it turns on the lamp itself. Then it sets up a keyboard
interrupt, so that the function
Keys
is called whenever a key is pressed.
Keys
is concerned with only three keys:
escape
,
-
, and
¯
. If
-
or
¯
is pressed, the
lamp setting (analog output port number 2) is changed by 200 mV, either up
or down.
is used to read the current value, and the change is added
to it, and the new value set with
:INT
lamp 2 /* d/a for lamp */
delta 200 /* shift amount */
uparrow 0x2600
dnarrow 0x2800
escape 0x1b
:FCT
main
{
1 0x0302
DIOSET
/* flow board on */
1 0x0005
DIOSET
/* lamp on */
&Keys
ONKBD
CLEAR
"Press up and down arrows\n"
"(escape to quit)"
0 ChangeLamp
IDLE
OFFKBD
}
Keys
{
GETKEY
:INT
k
k escape == IF
HALT
THEN
k uparrow == IF
delta ChangeLamp
THEN
k dnarrow == IF
delta
CHS
ChangeLamp
THEN
}
ChangeLamp
{
:INT
delta
lamp
AOVAL
delta + lamp
AOSET
1 5
POSXY
lamp
AOVAL
"Lamp at %4d mV"
}
Figure 23-35. Program to control the LED source by pressing the up and down arrow keys.
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...