Reference Manual
748384-C
September 2003
Rosemount Analytical Inc. A Division of Emerson Process Management Analyzer Variables
2-15
NGA2000 Reference
CASE_MAX_TMP
Direction Bidirectional
Binding
None
Type
Floating point variable
Value range
Specific to analyzer, typically 25 – 45
Units
°
C
Description
NDIR, PMD; Lower trip point for case fan control.
Usage
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.
See also
CASE_MIN_TMP
CASE_MIN_TMP
Direction Bidirectional
Binding
None
Type
Floating point variable
Value range
Specific to analyzer, typically 25 – 45
Units
°
C
Description
NDIR, PMD; Lower trip point for case fan control.
Usage
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.
See also
CASE_MAX_TMP
CASE_PGAIN
Direction Bidirectional
Binding
None
Type Floating
point
Value range
0.2
Units None
Description
FID only; the proportional gain for the temperature control algorithm.
Usage
Used for the control algorithm. This value has been experimentally determined, and
should not under any circumstances be changed.
See also
CASE_BIAS
CASE_IGAIN
CASE_SETP
CASE_SETP
Direction Bidirectional
Binding
None
Type Floating
point
Value range
0-50
Units
°
C
Description
FID only; the set point for the temperature control algorithm.
Usage
Used to determine the set point for the control algorithm. This value has been
experimentally determined, and should not under any circumstances be changed.
See also
CASE_IGAIN
CASE_PGAIN
CASE_BIAS