24
Linear Conversion
The command is described further as follows:
nn
represents the gauge type, or the configuration
of the datalogger’s input channel (see Table 2 and Table 3 in this section),
szzzz
represents the
zero reading for the transducer being read,
smmmm
represents the multiplier (calibration or
gauge factor) that will be applied to the reading to convert to engineering units and
soooo
is the
offset that will be applied to the gauge reading. The zero reading, gauge factor and offset can be
entered with a sign and decimal point. The maximum number of digits, including sign and
decimal point is 15. The entered value will display to a maximum of five places to the right of
the decimal point.
For all vibrating wire instruments (Gauge Types 0-5), manufactured after November 2, 2011 and
for all dataloggers (8002-1-X) with a firmware revision of 5.2.X and up, the basic formula for
calculation of displayed and stored values is as follows:
Display
=
((CurrentReading - ZeroReading)
×
Multiplier) + Offset
Equation 1 - Displayed Gauge Reading using Linear Conversion
NOTE: In Equation 1 (above), the “
CurrentReading
” is frequently referred to as
R
1
while the
“
ZeroReading
” is referred to as
R
0
Polynomial Conversion
The command is described further as follows:
nn
represents the gauge type, or the configuration
of the datalogger’s input channel (see Table 2 and Table 3 in this section),
saaaa
represents
polynomial coefficient A,
sbbbb
represents polynomial coefficient B and
scccc
polynomial
coefficient C. The polynomial coefficients can be entered with a sign and decimal point. The
maximum number of digits, including sign and decimal point is 15. The entered value will
display to a maximum of five places to the right of the decimal point.
For the vibrating wire instruments (Gauge Types 1-5), the basic formula for calculation of
displayed and stored values is as follows:
Display
=
(CurrentReading
2
×
A) + (CurrentReading
×
B) + C
Equation 2 - Displayed Gauge Reading using Polynomial Conversion
NOTE:
It is possible that a new datalogger might be used with an older sensor or vice
versa and because of equation differences, the output might be negative. As of
LogView version V2.1.1.X, an additional sensor configuration parameter is now
required, allowing LogView to compensate for old versus new sensor/datalogger
combinations. This new parameter:
Output Calculation
, determines whether the
sensor was calibrated using the formula:
G x (R
0
– R
1
)
or
G x (R
1
– R
0
).
As with the
gage factor, this information is available from the calibration certificate supplied with
each sensor. Please see the LogView User’s Guide or the online help section, “Sensor
Settings” available while running LogView.
