Emerson NGA2000 Reference Manual page 152

Reference Manual
748384-C
September 2003
TIME_PERIOD
Direction
Binding
Type
Value range
Units
Description
Usage
See also
VAL_HOLD
Direction
Binding
Type
Value range
Units
Description
Usage
See also
ZEROGAS
Direction
Binding
Type
Value range
Units
Description
Usage
See also
3-26 I/O Modules Variables
Output
None
Integer
1-255
Hours
ACAL, SCAL only; determines the period between calibration cycles.
This variable determines the time between calibration cycles. The normal setting
is 24. More frequent calibrations will reduce analyzer error due to drift but will use
more calibration gases and will increase the time spent not measuring the
process.
output
None
Enumerated
DISABLED; ENABLED
None
AIO, ACAL only; determines whether the output will hold while VALIDITY is
anything other than Normal.
If this variable is enabled, the analog output will hold at its last value while
VALIDITY is other than VALID.
IOMAINTHOLD
IOHOLDCAL
Bidirectional
None
4-element floating point array
Normally 0.
ppm
Zero gas. Element I refers to the zero gas for range 1, etc.
During zero calibration, the elements of ZERO are adjusted such that the value of
PVA resulting is within 0.02% of the full scale range value of the appropriate
element of ZEROGAS. If CALCHCKLIMITS is set to enabled, this will fail if the
change required is greater than the percentage of the full scale value given in
CALFAIL. The value of ZERO should be the same as the value of RAW - SIGNAL
while zero gas is flowing, and a zero may be effected by simply copying the value
of RAW-SIGNAL into the appropriate element of ZERO.
SPANGAS
ZERO
NGA2000 Reference
Rosemount Analytical Inc. A Division of Emerson Process Management