WIKA DI15 - Manual (Page 24)

Operating Instructions Digital Indicator DI15
V1.3 • 02/2011 - 24 -
6. Offset- and slope-adjustment
The offset and slope-adjustment function can be used for compensating the tolerance of the used sensor,
resp. for fine adjustment of the used transducer resp. transmitter.
Please note: The settings of the offset- / slope-adjustment will be cancelled, if no button was pressed for
more than 60 sec. Changes you may have made already won‘t be saved and will be lost!
Please note: The settings of the offset- / slope-adjustment and alarm-boundaries will automatically be reset to
factory default when any changes for the settings “InP”, “SEnS“ resp. “Unit“ had been made!
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 sec. the
value starts counting up or down, the counting speed will be raised after a short period of time.
The device also features a ‘overflow-function‘, when reaching the upper limit the device switches to the lower
limit, vice versa.
- Turn on the device and wait after it finished its built-in segment test.
- Press button 3 > 2 sec. (e.g. with a small screwdriver).
The device will be displaying „OFFS“ (offset).
- Use button 2 and button 3 for setting the desired zero point offset-value.
The input of the offset will be in digit resp. °C/°F.
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 be displaying “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:
Displayed value = (measured value – zero point offset) * (1 + slope adjustment [% / 100]).
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 ad-
justment of 102%)
- Press button 1 to validate the selection of the slope-adjustment. The display shows “SCAL“ again.
Examples for offset- and slope-adjustment:
Example 1: Connecting a Pt1000-sensor (with an offset error depending on the cable-length of the sensor)
The device displays the following values (without offset- or slope-adjustment): 2°C at 0°C and 102°C at 100°C
Therefore you calculated: zero point: 2
slope: 102 – 2 = 100 ( deviation = 0 )
You have to set: offset = 2 (= zero point-deviation)
scale = 0.00
Example 2: Connecting of a 4 ... 20mA-pressure-transmitter
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)
You have to set: offset = 0.08 (= zero point-deviation)
scale = 0.30 (= deviation / actual-slope = 0.06 / 19.94 = 0.0030 = 0.30% )
Example 3: Connecting of a flow-rate-transducer
The device displays the following values (without offset- or slope-adjustment): 0.00 at 0.00 l/min and 16.17 at 16.00 l/min
Therefore you calculated: zero point: 0.00
slope: 16.17 – 0.00 = 16.17
deviation: - 0.17 (= target-slope – actual slope = 16.00 - 16.17)
You have to set: offset = 0.00
scale = - 1.05 (= deviation / actual-slope = - 0.17 / 16.17 = - 0.0105 = - 1.05% )
Button 1 Button 2 Button 3