GE Optica, Operator'S Manual

Page: 63 / 150

January 2006
4-4 Programming the VGA Optica
Units of Measure
Table 4-1 below shows the units of measure available for each
parameter:
User Equations
In some applications an output may be needed that is not a simple
function of a single parameter, but a combination of two or three. One
or more user equations can be defined within the Optica to calculate
new parameters that meet the application’s requirements. The
equation can be formed from following elements:
•
the identifiers for the measured or derived parameter units (listed
in Table 4-2 on page 4-5).
•
the math operators + , – , × , / , (, ) and ^ (accessed through the math
key in SHIFT mode)
•
the math functions LOG and LN
•
constants
•
other user equations
The new parameter defined by this equation is given a name and can
be displayed or output just like any other parameter.
User Equations are entered from Menu 2 (see page 4-15). A list of
parameters and other elements is displayed. Each element is specified
by an identifier such as “A1.” Use these identifiers to form the
equation. In addition, another user equation can be used as an
equation element by entering its identifier.
Table 4-1: Available Units of Measure
Parameter Available Units
Humidity
Tdew °C, Tdew °F, %RH, Twet °C, Twet °F, ppmv,
ppmw, Grains/lb, Grains/SCF, g/kg, g/m
3
, lb/mft
3
,
kj/kg(0), kj/kg(32), BTU/lb(0), BTU/lb(32), pw(mbar)
Temperature
Tmp °C, Tmp °F, Tmp °K, Tmp °R
Pressure
psia, mbar, bar, Pa, kPa, mmHg, inHg, kg/Cm
2
,
Dyne/Cm
2