Device-specific Safety Instructions
Safety Manual
18 Operating Instructions, 06/2012, A5E03433511-05
3.6 Maintenance and checks
Checking the analyzer functions
We strongly recommend to check the function capability of the SITRANS SL at regular
intervals. This can be achieved by use of the verification kit.
Details of the verification procedure, the equipment and the time intervals are described in
the operating instructions, chapters 9 and 11.
Functional safety proof test
You should regularly check the safety function of the entire safety circuit according to
IEC 61508/61511.
The test interval is determined during calculation of each individual safety circuit in a system
(PFD
AVG
). The recommended testing interval depends largely on the application but should
not exceed one year.
To detect dangerous faults the SITRANS SL analog output and analog input shall be
checked with the following tests.
Table 3- 1 Proof test part 1
Step Action
1 Bypass the safety PLC or take another appropriate action to avoid a false trip.
2 Generate or simulate an alarm condition to force the SITRANS SL analyzer to exceed the low alarm
current output limit and verify the analog current value (e.g. by disconnecting pressure / temperature
input).
3 Restore the loop to full operation.
4 Remove the bypass from the safety PLC and restore to normal operation.
Table 3- 2 Proof test part 2
Step Action
1 Bypass the safety PLC or take another appropriate action to avoid a false trip.
2 Carry out an instrument verification according to section 9.1 of the operating instructions /1/.
3 Restore the loop to full operation.
4 Remove the bypass from the safety PLC and restore to normal operation.
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