62
8014084/ZWT7/V3-1/2020-06 | SICK
O P E R A T I N G I N S T R U C T I O N S | TRANSIC111LP
Subject to change without notice
5
SETTING AMBIENT PARAMETERS
5.1.1
Pressure compensation
Setting the value of the average process pressure value compensates the measurement
error more or less to zero in the immediate vicinity of the pressure value in question.
▸
Set the average pressure as parameter for the device. Either use the keypad,
“Process pressure: Display and settings (APP)”, page 37
“List of serial interface commands”, page 40
.
“Effect of process pressure compensation”, page 61
pressure compensation when the average process pressure is set to 1.2 bar(a). The
original error of approximately 1% of the measured value at 1.2 bar(a) is compensated to
zero. Pressure dependency remains for other values.
Pay particular attention that setting the pressure compensation does not shift the
parabola-like curve in
“Effect of process pressure compensation”
along the X-axis. This
means, even with compensation activated, pressure changes of the compensation value
have a more significant effect than with 1.013 bar(a).
0511-086
5.1.2
Background gas effects
Individual absorption line widths of O
2
gas are sensitive to intermolecular collisions
between O
2
and background gas molecules. This affects the measured O
2
values. The
magnitude of this effect depends on the amount and type of background gas molecules.
TRANSIC111LP factory calibration is carried out using dry N
2
and O
2
mixtures. Humidity
and CO
2
concentrations of the calibration gases are 0%. Apart from dry N
2
, all background
gases result in a percentage measured value error for O
2
measurement.
Carbon dioxide and water vapor are the most common gases requiring compensation.
Compensation for the average water and CO
2
contents of the background gas is integrated.
The compensation is based on manual user settings for the values for the water and CO
2
content of the background gas in the device. The water content is expressed in terms of
absolute humidity in g/m
3
H
2
O. Conversion Table,
see “Humidity Conversion Table”,
. The conversion formulas can be found in Section
.
NOTICE:
To disable pressure compensation, reset the average process pressure value to the
standard ambient air pressure of 1.013 bar(a). The magnitude of pressure
compensation is zero with this setting.
The allowable pressure range for compensation is 0.800 ... 1.400 bar(a).
All gases, apart from N
2
, influence the measured value.
Contact SICK Customer Service for information on the influence of further background
gases.
NOTICE:
Adapting compensation values to ambient conditions
●
When humidity and CO
2
compensation is/are activated, and when the ambient
conditions deviate from the ambient conditions during adjustment:
1
Set the water and CO
2
content according to the adjustment environment.
2
These settings then have to be changed back to represent those of the operating
conditions when the TRANSIC111LP is reinstalled in the process.
NOTICE:
Deactivating humidity and CO
2
compensation
▸
Set the values for the water and CO
2
content of the background gas to zero (factory
setting).
