Built-In Functions - Siemens SITRANS F Series Operating Instructions Manual

Fault Name/text
codes
C Low Impe‐
dance
d Flow Limit
Reverse Flow
A
Limit
Note
Reset of fault log (parameter 204) also resets all alarms. Once reset, only active alarms
become visible again.
9.2

Built-in functions

Empty pipe detection
Electrode impedance is measured with 800 Hz at 50 Hz mains frequency (960 Hz at 60 Hz
mains frequency). This is done by toggling the electrode control pin every 6 respectively 5
samples – the sample frequency is 9600 Hz. The impedance value is averaged over 100
measurements. The electrode impedance A and B are measured in turns.
The unfiltered impedance value (a fast warning indication) is compared with a limit and the
empty pipe warning is reported when it exceeds this limit – but only if the detection is ON and
if there is no overload failure.
During empty pipe detection the coil current is held OFF and the flow value is forced zero.
Default settings for Electrode Impedance Limit is 25 000 ohm corresponding to a water
conductivity of 20 µS/cm (10 000 ohm ≈ 50 µS/cm)
Insulation test
Insulation measurement is working like the normal measurement by excitation of the magnetic
coils in the sensor. Value is checked against a limit of 1.25 mm/s. A value above this limit results
in a failure report.
Measurement will NOT stop if an insulation fault occurs.
The last flow value is used for totalization during insulation test.
Insulation test interval according to register "Insulation Test Interval". Minimum 1 day between
tests.
SITRANS FM MAG 8000
Operating Instructions, 03/2020, A5E03071515-AH
Description
Measured electrode im‐
pedance is below low
impedance threshold
(parameter 542), i.e.
water has a high con‐
ductivity
The forward flow rate is
greater than the high
flow alarm limit (param‐
eter 553).
Reverse flow rate is be‐
low a preset threshold
(default -1E9)
Cause
● Water is polluted (e.g.
saltwater in fresh water)
● Water network failure –
pipe burst
Water network failure –
●
non-return valve is bro‐
ken
Diagnostics and Troubleshooting
9.2 Built-in functions
Remedy
-
Alarm is active until water resistance is
above low media alarm limit.
-
Alarm remains active until flow rate drops
below flow alarm limit.
-
Alarm remains active until reverse flow rate
drops below reverse flow alarm limit.
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