Siemens SITRANS F M MAG 8000, Руководство по эксплуатации, Страница: 87 / 164

Fault
codes Name/text Description Cause Remedy
L Leakage Lowest flow rate or vol‐
ume during leakage pe‐
riod has exceeded leak‐
age detection settings
● Leakage in water
network
Check setting and pipe installation.
Alarm is active until it is manually reset by
parameter 208.
Alarm reset resets information as does
leakage period reset (parameter 820).
E Empty Pipe Measured electrode im‐
pedance has exceeded
the empty-pipe detec‐
tion level (parameters
540, 541 and 334)
● Pipe is not filled with
water
Ensure sensor is filled with water.
Alarm remains active until fault condition is
resolved.
C Low Impe‐
dance
Measured electrode im‐
pedance is below low
impedance threshold
(parameter 542), i.e.
water has a high con‐
ductivity
● Water is polluted (e.g.
saltwater in fresh water)
-
Alarm is active until water resistance is
above low media alarm limit.
d Flow Limit The forward flow rate is
greater than the high
flow alarm limit (param‐
eter 553).
● Water network failure –
pipe burst
-
Alarm remains active until flow rate drops
below flow alarm limit.
A Reverse Flow
Limit
Reverse flow rate is be‐
low a preset threshold
(default -1E9)
●
Water network failure –
non-return valve is
broken
-
Alarm remains active until reverse flow rate
drops below reverse flow alarm 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)
Troubleshooting/FAQs
9.2 Built-in functions
SITRANS MAG 8000
Operating Instructions, 11/2018, A5E03071515-AE
87