Y=
Slope 2—User Compensation Control
The user can adjust the pressure vs. output curve using the
X=
,
Y=
, and
Z=
commands. The
Y=
command adjusts the slope of the pressure output curve for negative pressures. This modifies the
negative full scale slope. The range of adjustment is ±0.6%FS in 0.005% increments. Use the modi-
fied full scale value if the
F=
command is set. For differential units use one-half the range (FS=10 for
a 10psid). If there is an input error, then the command error flag in the
RS
command will be set and
no change will occur. See Figure 4.6 for command illustration. (Default:
Y=0
)
Inquiry: *dd
Y=
Action: *dd
WE
*dd
Y=
pp
pp
0 to ±120
(see
X=
for definition)
Z=
Offset—User Compensation Control
EEPROM Store: *dd
WE
*dd
SP=ALL
The user can adjust the pressure vs. output curve using the
X=
,
Y=
, and
Z=
commands. The
Z=
command adjusts the offset of the pressure output curve. This applies to all PPTs. The range of
adjustment is ±0.6%FS in 0.005% increments. For differential units use one-half the range (FS=10
for a 10psid). Use the customized full scale value (
F=
) as a multiplier.
For gauge type units, a zero offset null may be set by removing pressure and executing a
Z=CAL
command. For a differential unit, a zero offset null can be set by applying equal pressure to both
ports and execute a
Z=CAL
command.
For PPTR’s, the
Z=
command should be used to account for mounting orientation. The PPTR’s have
an oil filled stainless steel diaphragm that protects the sensor from corrosive media. This oil fill will
cause an offset in pressure reading when the PPTR is mounted in any position other than horizontal.
A method of calibration for the PPTR is described below for various mounting orientations.
If there is an input error, then the command error flag in the
RS
command will be set and no change
will occur. See Figure 4.7 for command illustration. (Default:
Z=0
)
Inquiry: *dd
Z=
Action: *dd
WE
* d d
Z =
{
p p
|
C A L
|
R E F
|
S E T
}
EEPROM Store: *dd
WE
*dd
SP=ALL
pp
0 to ±120
This number adjusts the pressure reading by adding (pp x 0.005% FS) to the
reading before outputting.
Pressure Output = [(pp x 0.00005) x (
M=
full scale)] + Pressure Reading
C A L
Sets the zero pressure condition to zero output. Offset is calculated and stored, then
applied to all readings thereafter. Set
Z=0
to cancel. The range of correction for the
CAL
command is the same as
pp
described above. If the correction is out of range, then the the
Z=
parameter will be set to a maximum value (+120 or -120).
Note
: When the
Z=CAL
command is executed and there is a deadband (
DS
) set, the output may not
read zero when it actually is. To read zero pressure, turn the deadband off (
DS=0
).
7 1
