Campbell CSAT3, Instruction Manual

Page: 59 / 72

Appendix B. Serial Communications with the CSAT3
B-3
Nassi-Shneiderman diagrams are given in FIGURE B-1and FIGURE B-2 for
collecting data using a PC and the RS-232 port. In FIGURE B-1, the PC is the
Trigger Source and the data acquisition system. In FIGURE B-2, the
anemometer is triggered by its internal timer and a PC is the data acquisition
system. Use the logic in FIGURE B-1 when the CSAT3 is measured along
with other analog/digital signals.
set RTS line low
repeat until finished collecting data
wait until timer = 1/(Execution Parameter)
process data
read wind data (U) or long status (P) from serial port
make other PC based analog/digital measurements
sent the U or P command
set timer to zero
send the An command to acquire signals
until CTS line is high
read CTS line
set RTS line high
FIGURE B-1. PC as the trigger source
set RTS line low
repeat until finished collecting data
process data
send W or S command
read wind data (W) or long status (S) from serial port
keep checking until there is data on the serial port
check for data serial port
send W or S command
send the An command to acquire signals
until CTS line is high
read CTS line
set RTS line high
FIGURE B-2. CSAT3 as the trigger source
B.2 CSAT3 Binary Data Output Format
Five words are sent by the CSAT3's RS-232 output. Words 0 through 3 are 16
bit signed integers and word 4 is 16 bit unsigned integer. The five words are
sent starting with word 0 and ending with word 4. A description of each word
is given in TABLE B-2.