WIKA A-AI-2 - Manual (Page 21)

6 Commissoning, operation
WIKA operating instructions, model A-AI-2 21
6.4 Offset and slope adjustment
The offset and slope-adjustment function can be used for compensating the tolerance of the used
sensor, resp. for vernier adjustment of the used transducer / transmitter.
Please note:
The storage of a configuration value will be occur by switching to the next
configuration value (via button 1). When configuration is active and no button is
pressed for more than 60 seconds the configuration will be cancelled. Stored
changes will not be lost!
Hint: The buttons 2 and 3 are featured with a ‘roll-function‘. When pressing the button
once the value will be raised (button 2) by one or lowered (button 3) by one. When
holding the button pressed for longer than 1 second the value starts counting up or
down, the counting speed will be raised after a short period of time.
Turn on the device and wait after it finished its built-in segment test.
Press button 3 > 2 seconds
The device will display “OFFS“ (Offset).
Use button 2 and button 3 for setting the desired zero point offset-value.
The input of the offset value is in digit. The value that had been set will be subtracted from the
measured value. (see below for further information)
Press button 1 to validate your selection. The display shows “OFFS“ again.
When pressing button 1 again, the device will display “SCAL“. (scale = slope)
Use button 2 and button 3 to select the desired slope-adjustment.
The slope adjustment will be entered in %. The value displayed can be calculated like this:
Display = (measured value – offset – di.Lo) * (1 + slope adjustment [% / 100] ) + di.Lo
Example:
The setting is 2.00 => the slope has risen 2.00 % => slope = 102%.
When measuring a value of 1000 (without slope-adjustment) the device would
display 1020 (with slope adjustment of 102 %)
Press button 1 to validate the selection of the slope-adjustment. The display shows “SCAL“
again.
Now you finished the offset and slope adjustment of your device. Press button 1 to finish the
adjustment and to switch over to display the measuring value.
Example for Offset and slope adjustment
Connecting of a pressure-transducer
The device displays the following values (without offset- or slope-adjustment):
0.08 at 0.00 bar and 20.02 at 20.00 bar
Therefore you calculated:
zero point: 0.08
slope: 20.02 – 0.08 = 19.94
deviation:
0.06 (= target-slope – actual-slope = 20.00 - 19.94)