Safety Characteristics - Siemens SITRANS P DS III Operating Instructions Manual

Functional safety

8.4 Safety characteristics

● Check both SITRANS P DS III devices as follows for a safety-instrumented system in
multi-channel operation (SIL 3).
● You check the status for warnings and alarms.
● You check the measured value limits.
● Simulate various currents and the minimum and maximum fault currents.
● Verify that the measuring tolerance is within the range of the application-specific
measuring error for the safety function.
– Set the measured value display to a unit of pressure in Mode 13.
– Check the zero point, e.g. in a pressureless state, for gauge and differential pressure.
– Check the zero point for absolute pressure, e.g. by applying a defined pressure.
– Check the upper limit of the measuring range (URL) and the upper limit of the span set
● Check the triggering of the safety function.
Activate button and function lock
After parameterizing/commissioning:
1. Set the lock mode in Mode 10 to write protection "L". See: Locking buttons and functions
(Page 94).
Operation via keys and HART communication is blocked.
2. Protect the keys from unintended change in the parameters, e.g. by lead-sealing.
8.4 Safety characteristics
The safety characteristics necessary for using the system are listed in the "SIL declaration of
conformity". These values apply under the following conditions:
● The SITRANS P pressure transmitter is only used in applications with a low demand for
the safety function (low demand mode).
● Communication with the HART protocol is used only for the following:
– Device configuration
– Reading diagnostics values
– However, it is not used for operations critical to safety. In particular, the simulation
● The safety-related parameters/settings have been entered by local operation or HART
communication before commencing safety-related operation. Check the
parameters/settings on the device display. See Settings (Page 149).
● The safety function test has been concluded successfully.
● The transmitter is blocked against unwanted and unauthorized changes/operation.
150
(URV) for gauge, absolute and differential pressure by applying a defined pressure.
– Use mode 13 to reset the measured value display to the desired unit.
function must not be activated in safety-related operation.
SITRANS P DS III with HART
Operating Instructions, 06/2013, A5E00047092-09