Section 6
6-12
Interfacing
Measuring Raw (Non-Linear) Analyzer Output
To measure the non-linearized voltage output of the CO
2
or H
2
O analyzer
(0.1 second response time) with a meter or data logger:
●
Connect the positive input of the data logger to the terminal labeled
CO
2
0.1S
or
H
2
O 0.1S
(see Figure 6-3).
●
Connect the negative input to the terminal labeled
SIG GND
. If the
cable from the data logger is shielded, the shield can be connected to the
CHASSIS GND
terminal.
●
To measure analyzer temperature or the voltage output with a different
response time, connect the appropriately labeled terminal to the positive
input of another channel on the data logger.
The resolution which the data acquisition device should have is dependent
upon the noise level of the analyzer (0.2
µ
mol/mol C0
2
typical, 0.4
µ
mol/mol maximum, or 0.05 mmol/mol H
2
O typical, 0.2 mmol/mol
maximum).
DAC1 5V
DAC1 100mV
DAC1 20mA
DAC2 5V
DAC2 100mV
DAC2 20mA
SIG GND
SIG GND
CO
2
0.1S
CO
2
1S
H
2
O 0.1S
H
2
O 1S
SIG GND
TEMP 5V
AUX
CHASSIS GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
DATA LOGGER
Figure 6-3. Connection of data logger for non-linear output.
