Emerson NGA2000 Reference Manual page 71

NGA2000 Reference
CAL_PRESS
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CAL_PRESSURE
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CAL_RAW_SIG
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CAL_VALIDITY
Direction
Binding
Type
Value range
Units
Description
Usage
See also
Rosemount Analytical Inc. A Division of Emerson Process Management
Bidirectional
None
Floating point
189-650
hPa
FID only; expected sample pressure during calibration.
Used to determine the gain settings, along with the fuel type, CARBON_ATOMS and
the full scale range values. The actual value read in PRES_IS is not used in order to
avoid hysteresis problems. If the wrong value is set, the gain may be wrong and the
circuitry may saturate. This can be seen by examining the value of RAW SIGNAL
during span, it should be less than 1,000,000. In general, the value of CAL_PRESS
should be 189 (= 3 psig) for high range applications.
CAL_PRESSURE
Bidirectional
None
Floating point
189-650
hPa
FID only; actual sample pressure during calibration.
The actual sample pressure at calibration time. This is used together with the
PRESS_IS first element or BAROMETER to compensate PVA for any sample
pressure changes. This value should be within about 5% of CAL_PRESS for correct
operation. Lower values are safe, higher values may saturate the amplifiers.
CAL_PRESS
Output
None
2-element floating point array
20
0 - 2 (about 1 million) except CLD, 0 - 0 – 65535
None
Raw signal at last zero (element 1) or last span (element 2).
Shows the raw signal (ADC reading) during the last zero or span, but only if the zero
or span was successful. These numbers should be reasonable based on the zero
gas and span gas used, typically half of the full scale range for the zero, and
between 20% and 80% of the rest of the range for the span. If the numbers are the
same, it implies that the same gas was used for both operations, which would be an
error.
CAL_RNGHI
Output
CAL_VALIDITY
Enumerated type
None; 1; 2; 3; 4; and all combinations to 1 & 2 & 3 & 4
None
Ranges with valid zero and span calibrations
Shows which ranges were able to be both zeroed and spanned at the last calibration
CAL_ERR_MSG
Reference Manual
748384-C
September 2003
Analyzer Variables 2-9