Emerson NGA2000 Reference Manual page 80

Reference Manual
748384-C
September 2003
CRUDE_NOISE
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CUR_SIG_GAIN
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CURR_SENS
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CURR_WAS
Direction
Binding
Type
Value range
Units
Description
Usage
See also
2-18 Analyzer Variables
Output
None
Floating point
0 - 100, typically
ppm
Shows the current noise level
Calculated by the analyzer module, this shows the standard deviation of the signal,
as long as a significant slope to the signal is not detected. In other words it is only
meanignful when the signal is stable. It is expressed in ppm, as if it were a reading.
PVA
Output
None
Integer
1-99
Percent
NDIR only; shows the current setting of the signal gain digital potentiometer.
Used to report this setting, as opposed to the variable that sets it.
SIGNAL_GAIN
Output
None
Floating point
0-5
Amps
NDIR only; measured source current.
Measures the current through the IR sources. This should be about 1 amp, more
(about 1.24 amps) for long cell benches (such as low level CO) and less for short
benches such as high level C02 (typically 0.85 amps). Excessive source current will
stress the detector causing the response to jump unpredictably. A source current
that is too low will reduce the sensitivity of the bench, increasing noise and drift. This
is set at the factory, and should not be lightly adjusted.
SOURCECURR
Output
None
Floating point
0-5
Amps
NDIR only; historical source current.
Shows the value of source current at manufacturing check out time. This is
automatically written by the manufacturing data storage function, and it should not be
over-written.
CURR_SENS
NGA2000 Reference
Rosemount Analytical Inc. A Division of Emerson Process Management