Reference Manual
748384-C
September 2003
I/O Modules Variables
Rosemount Analytical Inc. A Division of Emerson Process Management
3-26
NGA2000 Reference
TIME_PERIOD
Direction Output
Binding
None
Type Integer
Value range
1-255
Units Hours
Description
ACAL, SCAL only; determines the period between calibration cycles.
Usage
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.
See also
VAL_HOLD
Direction output
Binding
None
Type Enumerated
Value range
DISABLED; ENABLED
Units None
Description
AIO, ACAL only; determines whether the output will hold while VALIDITY is
anything other than Normal.
Usage
If this variable is enabled, the analog output will hold at its last value while
VALIDITY is other than VALID.
See also
IOMAINTHOLD
IOHOLDCAL
ZEROGAS
Direction Bidirectional
Binding
None
Type
4-element floating point array
Value range
Normally 0.
Units ppm
Description
Zero gas. Element I refers to the zero gas for range 1, etc.
Usage
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.
See also
SPANGAS
ZERO
