Emerson NGA2000 Reference Manual page 77

NGA2000 Reference
CASE_MAX_TMP
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CASE_MIN_TMP
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CASE_PGAIN
Direction
Binding
Type
Value range
Units
Description
Usage
See also
CASE_SETP
Direction
Binding
Type
Value range
Units
Description
Usage
See also
Rosemount Analytical Inc. A Division of Emerson Process Management
Bidirectional
None
Floating point variable
Specific to analyzer, typically 25 – 45
°C
NDIR, PMD; Lower trip point for case fan control.
The NDIR or PMD cooling fan has a duty cycle that extends between the lower trip
point and the upper trip point. At the upper value, the duty cycle is 50%. It is possible
to turn the fan completely ON or 50% ON by setting these variables so that the
measured temperature is outside their range. This can help determine if any
measured diurnal change is due to temperature changes or not.
CASE_MIN_TMP
Bidirectional
None
Floating point variable
Specific to analyzer, typically 25 – 45
°C
NDIR, PMD; Lower trip point for case fan control.
The NDIR or PMD cooling fan has a duty cycle that extends between the lower trip
point and the upper trip point. At the former value, the duty cycle is 50%. It increases
linearly until the higher trip point.
CASE_MAX_TMP
Bidirectional
None
Floating point
0.2
None
FID only; the proportional gain for the temperature control algorithm.
Used for the control algorithm. This value has been experimentally determined, and
should not under any circumstances be changed.
CASE_BIAS
CASE_IGAIN
CASE_SETP
Bidirectional
None
Floating point
0-50
°C
FID only; the set point for the temperature control algorithm.
Used to determine the set point for the control algorithm. This value has been
experimentally determined, and should not under any circumstances be changed.
CASE_IGAIN
CASE_PGAIN
CASE_BIAS
Reference Manual
748384-C
September 2003
Analyzer Variables 2-15