Sea-Bird Scientific SUNA V2, Руководство пользователя

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These equations can also be written as:
C
nitrate
= A
0
+ A
1
× V, and
C
nitrate
= B
0
+ B
1
× I
where—
A
1
= (DAC
max
- DAC
min
) / (V
max
- V
min
) is the voltage scale coefficient
A
0
= DAC
min
- A
1
× V
min
is the voltage offset coefficient
B
1
= (DAC
max
- DAC
min
) / (I
max
- I
min
) is the current scale coefficient
B
0
= DAC
min
- B
1
× I
min
is the current offset coefficient
Calibrate the sensor in-system
The voltage and current values in a deployed system may be different from the nominal
values and should be used instead.
1. Use a Y-cable to connect the sensor to the data collection device and a PC.
2. Select the Sensor menu, then Advanced , then DAC Calibration . Push Low, then
High, to get the analog output for the lower, then upper values of the nitrate DAC
range.
3. Use these values to calculate the in-system scale and offset coefficients.
A
1
= (DAC
max
- DAC
min
) / (V
high
- V
low
) is the in-system calibrated voltage scale coefficient
A
0
= DAC
min
- A
1
× V
low
is the in-system calibrated voltage offset coefficient
B
1
= (DAC
max
- DAC
min
) / (I
high
- I
low
) is the in-system calibrated current scale coefficient
B
0
= DAC
min
- B
1
× I
low
is the in-system calibrated current offset coefficient
7.2 Terminal program
The user can communicate with the sensor through the manufacturer-supplied software,
or by use of a terminal program through the serial port on a PC. Examples of terminal
programs include PuTTY, Tera Term, and Bray.
When power is supplied to the sensor, the sensor goes into a low-power "standby" mode.
Any activity on the input line puts the sensor to the "SUNA>" command interface within
three seconds. The sensor returns to low-power standby after a user-selected period of
time with no communication.
1. Connect the serial cable to the sensor and the PC.
2. Connect the serial cable to an 8–15 VDC, 1 A minimum, power supply.
3. Start a terminal program.
a. Set up the communication values if necessary: 8 bit, no parity, 1 stop bit, no flow
control.
b. Go to Setup , then Serial Port .
c. If necessary, change the baud rate to 57600. Push OK.
Reference
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