Measuring Sensitivity Of The Acoustic Channels Via Parameters P.1 To; Main Alarm Threshold Via Parameters P.6, P.8, P.10 And; Pre-Alarm Threshold Via Parameters P.5, P.7, P.9 And - Siemens 7MJ2000-1A 00 Series Operating Instructions Manual

8.2.2 Measuring sensitivity of the acoustic channels via parameters P.1 to P.4.
The setting "on L" or "on H" is recommended for normal measurement. Should a measured
value greater than 20 dB already be displayed with a fault-free pump in operation (e.g.
through pseudoactivation), a reduction in the sensitivity is recommended by setting "on_L" or
"on_H".
Note
The following applies for all acoustic emission sensors on a pump:
All acoustic channels must be set to the same measuring sensitivity.
Note
Changing the measuring sensitivity
If you have reduced the measuring sensitivity, then all measured values for the acoustic
channels must be read off again. Use the new measured values for the further configuration.
8.2.3 Main alarm threshold via parameters P.6, P.8, P.10 and P.12
If the set limit (period greater than response time P.13) is exceeded , the main alarm gives
the report that there is a cavitation to which the leak can be traced. A leak can be caused by:
● Damaged valve seats
● Damaged valve body
● Closing function is impeded
● Solid matter stuck in valve
In certain cases, depending on the design, mode of operation and the pumped medium, self-
cleaning effects or self-correcting effects can occur, which cause the fault to disappear.
Not every signal necessarily indicates permanent damage. Therefore, the limit value for the
main alarm should be set so that not every slight rise in the level causes a signal - the pre-
alarm can be used for this purpose if necessary.
Set the limit value for the main alarm at a value which is around 6 dB over the largest of the
measured values read off.
8.2.4 Pre-alarm threshold via parameters P.5, P.7, P.9 and P.11
Damage development can be detected with the pre-alarm. Frequency and time intervals are
used here as statistical aids.
Select the limit value such that it performs the task you want it to. We recommend that you
set the pre-alarm to half the value of the main alarm limit.
SITRANS DA400 for oscillating positive displacement pumps
Operating Instructions, 09/2008, A5E00841120-03
8.2 Recommendation for the selection of parameters
Commissioning
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