Honeywell PPT User Manual page 61

O= Offset Pressure Window
Offset the analog pressure window to reassign the minimum pressure value for the lowest analog
output. This command sets a pressure offset value from 0 to 99% of full scale. An O= inquiry reads
the value in percent of full scale (F= value). This command is used with the W=, L=, and H= com-
mands to customize the size of the PPT analog output window and analog output voltage. This
command has no effect on the digital readings. This command is enabled by the AN command. If
there is an input error, then the command error flag in the RS command will be set and no change
will occur. (Default: O=0 )
For example when L=0 and H=0, if a 20 psia (or 20 psig) unit had the offset window set to O=20,
then the analog 0V output would begin at 4 psi (20% of 20 psi) and be rescaled to 5V at 20 psi. Use
the W= command (W=80) to adjust the span if only a portion of the remaining range is of interest. If
the range of 4psi to 16psi is desired to be windowed onto the 0 to 5 volt scale then a W=60 would be
used (60% of 20=12 psi) + 4 psi = 16 psi FS.
If a 20 psid unit had the offset pressure window set to O=20, then the offset pressure would be 8 psi
(20% of 40 psi). The analog 0V output would begin at -12 psi, cross 2.5V at 4 psi, and output 5V at 20
psi. If the W= value was > 80, then it is automatically set to 80.
Note: Setting a window offset (O=) value that causes the maximum output pressure to exceed 5V
will automatically scale the pressure window (W=) value to maintain the 5V limit.
Inquiry: *dd O=
Action: *ddWE
*ddO=pp
pp 0 - 99 This number is a percent multiplier (%) of the full scale pressure that sets the
minimum pressure value corresponding to the lowest analog output. It can also be thought
of as an offset, or sliding, of the pressure window. For O=0, the offset is zero pressure and
the original pressure value for 0V (or L= value) output is used. For O>99, the pressure
offset window will be 99%FS.
EEPROM Store: *ddWE
5 5
*ddSP=ALL