Campbell CR10 PROM Instruction Manual download pdf (Page 11)

CSAT3 THREE DIMENSIONAL SONIC ANEMOMETER

6

TABLE 5-6. CSAT3 Analog Output Wiring

Description Color

u

x

sig high Brown

u

x

sig low Black

u

y

sig high Red

u

y

sig low Black

u

z

sig high Green

u

z

sig low Black

c sig high White

c sig low Black

shield Clear

TABLE 5-7. FW05/FWC-L35 Fine Wire

Thermocouple

Description Color

Signal High Purple

Signal Low Red

6. CSAT3 OUTPUTS

The CSAT3 has three signal outputs: SDM,

RS-232, and analog. Campbell Scientific

recommends that the SDM output be used when

ever possible, followed by RS-232, and finally

analog. Table 6-1 summarize the difference

between the three output options. In general SDM

communications has the following advantages:

lowest CSAT3 current drain, best control and

diagnostics, and highest data resolution.

TABLE 6-1. CSAT3 Outputs.

SDM RS-232 Analog

Typical

Current

Drain @ 10

Hz

51

mA

89

mA

99

mA

External

Trigger

Source

yes yes no

Output

Dynamic

Range

19 bit 19 bit 12 bit

Diagnostics

Available

yes yes no

6.1 SDM

6.1.1 CR23X, 21X, CR10(X)

SDM is a Campbell Scientific communication

protocol used between a Campbell Scientific

datalogger and a smart sensor. This protocol

uses control ports 1, 2, and 3 to communicate

with the CSAT3. With a 21X, single ended

analog input channel 1 (labeled 1H) and a 10 K

resistor is used in conjunction with control port

1. SDM protocol allows synchronized

measurement and rapid communication

between a datalogger and the CSAT3. The

datalogger instruction, SDM-CSAT3 (P107), is

used to communicate with the CSAT3 over the

SDM bus.

6.1.2 CR9000

SDM communications between the CR9000 and

CSAT3 is achieved via the 9 pin CSI serial I/O

port on the 9080 peripheral and memory card.

The CR9000 instruction CSAT3() is used to

communicate with the CR9000 over the SDM

bus.

6.2 RS-232 OUTPUT

The Windows CSAT3 monitor software can be

used to graph the CSAT3 data in real time or

collect time series via the RS-232 serial port.

Appendix B contains detailed information on the

CSAT3 RS-232 commands.

6.3 ANALOG OUTPUT

The anemometer can be programmed to output

four analog signals that correspond to u

x

, u

y

, u

z

,

and c. These signals range ±5000 mV. The

analog output is enabled using the Windows

CSAT3 monitor software using the PC’s and

CSAT3’s RS-232 serial port. The u

x

and u

y

components of wind have two output ranges, low

range (±32.768 m s

-1

) and high range (±65.536

m s

-1

). These ranges are changed using the

Windows CSAT3 monitor software. Low range

is adequate to measure wind speeds ±32.768 m

s

-1

. Table 6-2 gives the multipliers and offset for

all the anemometer outputs in m s

-1

.

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 29 30

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