Customized Pressure Range; Figure 4.3-Custom Slope (X=) Options; Figure 4.4-Custom Offset (Z=) Options - Honeywell HPB User Manual

HPB/HPA User Manual

4.4 CUSTOMIZED PRESSURE RANGE

The user can adjust the pressure vs. output value transfer curve using the X=, Z= and F= commands. The X=
command adjusts the slope of the pressure output curve. The Z= command adjusts the offset of the pressure
output curve. The range of adjustment for X= and Z= commands is ±0.6%FS in 0.005% increments. The F=
command can change the full scale pressure span to any value between 50% and 100% of the factory specified
range (M=).
The purpose of these commands is to allow the user to provide compensation for the pressure values specific
application. This type of adjustment is made after the HPB temperature compensates the pressure reading
to an
according to the factory calibration. The user-supplied values (X=, Z=) are used as an mx+b correction. The X=
command supplies the slope adjustment, or ‗m', value and the Z= command supplies the offset adjustment, or
‗b', value.
Figures 4.3 and 4.4 illustrate these commands.
Figure 4.3—Custom Slope (X=) Options
The user compensated pressure output can be expressed in terms of X= slope values ‗m' where m=0 to ±120.
The offset value, Z=, can be expressed as ‗b' where b=0 to ±120.
Pressure Output = [(1 + m x 0.00005) x Pressure Reading] + [(b x 0.00005) x (full scale)]
The F= command is used in conjunction with the X= and Z= command to customize the full scale range and user
compensation of the HPB. The F= command allows the user to reduce the full scale range of the HPB as much as
one-half the factory FS value. The F= command value can have up to 5 significant digits with a decimal point.
Enter an F=0 command to disable this function and return to the factory default (M=) full scale value. Using the
F= command, the maximum allowable full scale pressure is the M= value and the minimum allowable FS
pressure is (0.5 x the M= value). The new F= value becomes the standard FS number used for other commands
and range calculations. (Note that the accuracy specification is always referenced to the factory (M=) full scale
value.) For example, to customize the full scale range of a 1200 mBar (900mm Mercury - mmhg) device to 800
mmhg, first select the desired display units using the DU command. Enter the command *ddWE followed by a
*ddDU=mmhg. Then enter a *ddWE followed by a *ddF=800. The full scale pressure for this unit is now 800
mmhg.
18
Figure 4.4—Custom Offset (Z=) Options
www.honeywell.com