Siemens LC 500 Number Description, Start Up, Read Additional Transmitter Status, = 47.22 pF

Start Up

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 LC 500 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 LC 500.

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 LC 500, 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

Page 48 SITRANS LC 500 – INSTRUCTION MANUAL 7ML19985GE01