Siemens SIPART Series - 9.4.3.3 Description of parameter C

Parameterizing/addressing
9.4 Description of parameters
SIPART PS2 with and without HART
Operating Instructions, 10/2013, A5E00074631-11
181
9.4.3.3
Description of parameter C
C. LEAK - pneumatic leakage
Use this parameter to activate the pneumatic leakage test. This test can be used to
determine possible pneumatic leakages. Depending on the direction, changes in the position
and the internal manipulated variable used for it are continuously recorded and filtered for
this purpose. The filter result is used to form an indicator, which allows drawing a conclusion
about a possible leakage.
Note
Accuracy of results
Note that this test deli
vers unambiguous results only in the case of single-acting, spring-
loaded actuators.
Set the "On" parameter value to activate the test. Sub-parameters are displayed. Sub-
parameters are described below.
The current value is displayed in the "15 ONLK" diagnostics parameter. The positioner
triggers a fault message if the current value exceeds one of the three configurable limit
thresholds.
The factory setting is "OFF".
C1.LIMIT - limit of the leakage indicator
Use this sub-parameter to set the limit of the leakage indicator in percent. Set the limit in a
range from "0.1" to "100.0". If no leakage exists, the leakage detection is automatically
calibrated in such a way during the initialization (see chapter "Commissioning (Page 113)")
that the leakage indicator remains below the value 30. If a value above 30 is displayed, this
means that a leakage exists. "30.0" is therefore an advisable setting for the parameter. After
a certain time this limit can be varied slightly depending on the application. To optimize the
sensitivity of the leakage detection to your specific application, follow these steps:
1. After initializing the positioner automatically, use a calibration device to initiate a ramp
movement.
2. Conditions for the ramp movement:
– The ramp covers the normal operating range of the valve.
– The steepness of the ramp matches the dynamic requirements of the corresponding
application.
– The characteristic of the ramp corresponds to the characteristic of the setpoint that
actually occurs.
3. During the ramp movement, the "15 ONLK" diagnostics parameter provides information
about the actual values. Define the limit of the leakage indicator accordingly.
The positioner triggers a fault message if the current value exceeds one of the three
configurable limit thresholds. How to set the three limit thresholds is described below.
The factory setting is "30.0".