More Information
‣
Environmental Compensation (page 15)
9.3.3 Limits of Adjustment
The probe limits the amount of adjustment that is allowed to the CO
2
measurement. The
maximum correction that you can apply is 1000 ppm + 25 % of the probe’s uncorrected
reading. Previous user adjustments do not aect this limit (the correction is not cumulative).
This feature limits the possible error introduced by incorrect adjustment.
For example, if you are adjusting using a 5000 ppmCO
2
calibration gas, the maximum
correction you can apply is approximately 2250 ppm. Attempting to apply a greater
adjustment will fail.
Notification of failure from the probe depends on the interface you are
using for adjustment.
9.3.4
Adjustment Types
You can adjust the CO
2
measurement of the probe in one or two points.
• One-point adjustment is recommended if you are interested in maintaining a fixed CO
2
level. For best result, use a calibration gas with a CO
2
concentration that is close to the
intended level.
• Two-point adjustment is recommended if you typically measure a variable CO
2
level.
Available adjustment functions depend on the interface you use to operate the probe. If you
want to integrate the functionality into a control system, the Modbus interface and the
Vaisala industrial protocol are recommended. If you want to compare the reading of the
probe to a reference instrument and adjust it accordingly, use an MI70 hand-held indicator
and a reference probe.
Vaisala Industrial Protocol
Vaisala industrial protocol supports 1-point and 2-point adjustment with the cco2
command.
Configuration of the environmental compensation settings can be done using
serial line commands.
Modbus
The environmental compensation settings can be configured using Modbus registers.
MI70 Hand-Held Indicator
The MI70 hand-held indicator supports 1-point adjustment, either using a calibration gas or
using a reference instrument that is connected to the MI70.
Vaisala Insight PC software
You can carry out 1-point and 2-point adjustments and change the environmental
compensation settings with the Insight software (requires USB cable 242659).
Vaisala Indigo transmitters
You can use the Indigo transmitter's wireless
configuration interface to carry out 1-point and
2-point adjustments and change the environmental compensation settings.
GMP252 User Guide M211897EN-D
96
To Next Page
Loading...
