Vaisala Indigo 201 - Environmental Compensation; Figure 23 Measurement Selections, CO 2 Probe Example

• The output keeps rising until the measurement is 21 %CO
2
, at which point the probe
outputs 5.25 V.
• If the CO
2
level rises above 21 %CO
2
, the output still remains at 5.25 V.
• If the CO
2
level rises above 22 %CO
2
, the output enters the error state, which is 0 V for
the 0 ... 5 V output.
Output
voltage (V)
Time
0.00
In error state at
>220000 ppm
(200000 ppm + 10%)
5.00
5.25
Clipped at
210000 ppm
(200000 ppm + 5%)
Regular
measurement
Output clipping limit
Error level
Figure 23 Example of Analog Output Overrange Behavior
This example uses output scaled to 0 ... 5 V and 0 ... 200000 ppm, error level set to 0 V,
clipping set to 5 % overrange, and error limit set to 10 % overrange. CO
2
concentrations
(ppm) are indicated for the clipping point and error limit point.
Indigo 201 User Guide M211877EN-E
48