Page 48
SITRANS LC500 – OPERATING INSTRUCTIONS
7ML19985GE04
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The capacitance value for a 17% change in level is 17 * 2.08 = 35.37 pF.
The capacitance value for 0% is 52 – 35.37 = 16.62 pF (initial capacitance value).
The capacitance value for 100% is (100 * 2.08) + 16.62 = 208 + 16.62 = 224.6 pF.
3.
Enter the calculated values for 0% and 100%, to calibrate the SITRANS LC500 as
described in Example 2.
Example 4
For situations involving the re-adjustment of the LRV where the actual value is
determined to be one value but the measurement shows a different value.
1.
Switch on the 275 and establish connection with the SITRANS LC500.
a. Select:
Online
b. Select: PV
The measured value can now be read continuously.
2.
Write down the measured value in pF: assume it is 80 pF.
Example:
Assume that the URV is set to 240 pF, that the actual value is 17%, but the
measurement is showing a different value.
the measured value = 80 pF
(100 – 17) %
= 83%
(240 – 80) pF
= 60 pF
160
pF
= 1.927 pF per %
83%
The capacitance value for 100% (URV) is 100 * 1.927 = 192.7pF
The new LRV should be 240 –192.7
= 47.22 pF.
3. Adjust URV and LRV by following the steps in Example 2.
If the DCS and/or the 275 are fitted with the Device Descriptor for the SITRANS LC500,
more functions can be used.
The available functions are
:
Number
Description
(48)
Read Additional Transmitter Status
(38)
Reset Configuration Changed Flag
(128)
Set Alarm Select
(129)
Adjust for Product Build-up on Sensor