9.5 Recalibration
If you want to fit the pressure transmitter with a diaphragm seal you can recalibrate the
sensor using the "Low Sensor Trim" (V7H4) and "High Sensor Trim" (V7H5) parameters.
The highest measurement accuracy is obtained when the value for the "Low Sensor Trim"
(V7H4) parameter corresponds to the 4 mA calibration value (V0H1/V0H3) and the value
for the "High Sensor Trim" (V7H5) parameter to the 20 mA calibration value (V0H2/V0H4).
There must be a known reference pressure when setting a new lower or upper sensor
characteristic curve value. The more accurate the reference pressure is during
recalibration, the higher the accuracy of the pressure transmitter will be later. A new value
is assigned to the applied pressure using the "Low Sensor Trim" (V7H4) and "High Sensor
Trim" (V7H5) parameters.
#
Matrix Path through the
menus
Entry
1
A device with a sensor: –0.5…0.5 bar must
be recalibrated for the 0.0…0.4 bar range.
Main group: Additional functions
2
Reference pressure of 0.0 bar for "Low
Sensor Trim" (V7H4) value.
3
The value 0.0 is assigned to the applied
pressure.
V7H4
➤
Low Sensor
Trim
0.0 bar
Confirm
4
Reference pressure for "High Sensor Trim"
(V7H5) value = 0.4 bar.
5
The value 0.4 is assigned to the applied
pressure.
V7H5
➤
High Sensor
Trim
0.4 bar
Confirm
6
The sensor is now calibrated for 0.0…0.4 bar.
The "Low Sensor Trim" and "High Sensor Trim"
parameters indicate:
Low Sensor Trim = 0.0 bar
High Sensor Trim = 0.4 bar
Note!
•
By entering the reset code "2509" in the V2H9 matrix field, you return the following
parameters to the factory setting:
– Low Sensor Trim = Low Sensor Limit (V7H4 = V7H6),
– High Sensor Trim = High Sensor Limit (V7H5 = V7H7),
– Zero Correction Value (V9H6) = 0.0
•
When the "Low Sensor Trim" (V7H4) and "High Sensor Trim" (V7H5) values are too
close together, the device outputs the error message "E 104".
Note!
0
-0.5
0.5
0.5
0
-0.5
sensor characteristic
curve
pressure
e.g. [bar]
Low
Sensor
Trim (V7H4)
Sensor characteristic curve for the default factory calibration
– here for a differential pressure sensor: –0.5…0.5 bar
applied reference
pressure e.g. [bar]
High
Sensor
Trim (V7H5)
BA174Y87
0
0
0
-0.5
0.5
0.5
0
-0.5
0.4
0.4
new sensor
characteristic curve
presssure
e.g. [bar]
Low
Sensor
Trim (V7H4)
"new"
Sensor characteristic curve – recalibrated for the
measuring range: 0.0…0.4 bar
applied reference
pressure e.g. [bar]
High
Sensor
Trim (V7H5)
"new"
BA174Y92
9 Maintenance and Repair
Deltabar S
66
Hauser
