Checking Safety Function/Proof Test - Siemens SITRANS P DS III Operating Instructions Manual

Functional safety
8.5 Maintenance/check
8.5.2

Checking safety function/proof test

Requirement
● You should preferably check the safety function while the device is installed. If this is not
possible, you can also check the safety function when the device is not installed. Make
sure that the pressure transmitter is mounted in the same position for testing as it is in the
system.
● Observe the information in the section Write protection (Page 150).
● If you are using add-on parts, also see the tests in section Add-on parts (Page 140).
Procedure
1. Make sure that the test does not inadvertently result in an emergency shutdown of the
system.
2. Make sure that there are no active warnings or error messages.
3. Check temperature sensors (Page 135).
4. Check response time of pressure transmitter (Page 135).
5. Conduct a two-point measurement:
Two-point measurement ≥ 10% of the maximum measuring range. (Page 135)
- or -
Two-point measurement ≥ 50% of the maximum measuring range. (Page 138)
6. Make sure that the pressure transmitter is in measuring mode.
7. After the test, make sure that the emergency shutdown of the system is working again.
8. Disable the write protection.
Result
If you are conducting the test as described, you will detect dangerous faults to a certain
degree that are not detected by runtime diagnostics:
● With two-point measurement ≥ 10% of the maximum measuring range: 89% of the faults
are detected.
● With two-point measurement ≥ 50% of the maximum measuring range: 98% of the faults
are detected.
Interval
● Check the pressure transmitter regularly for proper function (proof test) to detect
influences which could reduce the functionality of the pressure transmitter in time.
● Select the interval according to the process and ambient conditions of the installation
location of the pressure transmitter.
134
SITRANS P DS III/P410 with PROFIBUS PA
Operating Instructions, 02/2016, A5E00053276-08