Siemens SITRANS LG250 Operating Instructions Manual page 40

To avoid possible errors during parameterization in a non-safe user
environment, a verification procedure is used that makes it possible
to detect parameterization errors reliably. For this, safety-relevant
parameters must be verified before they are stored in the device. In
normal operating condition, the instrument is also locked against
parameter changes through unauthorized access.
For this reason, the instrument is shipped in locked conditon. The PIN
in the delivery status is "0000".
Character string comparison and serial number
You first have to carry out the character string comparison. This is
used to check the character respresentation.
Confirm if the two character strings are identical. The verification texts
are provided in German and in the case of all other menu languages,
in English.
Afterwards you confirm that the serial number of your instrument was
carried over correctly. This is used to check device communication.
In the next step, the instrument checks the data of the measurement
and decides by means of the evaluation results if a functions test
is required. If a function test is necessary, the following message is
displayed.
In this case, you have to carry out a function test.
Function test
During a function test, you have to test the safety function of the
instrument in the vessel with the original medium.
You can find the detailed sequence of the function test in chapter
"Functional safety (SIL)"
For this purpose, you should know the filling height of the vessel as
well as the min. and max. levels respectively for 4 and 20 mA. You
then can calculate the respective output current.
Measure the output current of SITRANS LG250 with a suitable multi-
meter and compare the measured output current with the calculated
output current.
You have to determine the permissible deviation of the values
yourself. This deviation depends on the the accuracy requirements of
40 SITRANS LG250 - Operating Instructions PBD-51041387