
Commissioning
FLOWSIC600 · Technical Information · 8010125 V 4.0 · © SICK AG
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Table 21
Path warnings
Monitored
measurement
Configurable User
Warning parameters
Default
value
Notes
Default
activation
state
1
Turbulence
2
Path turbulence
6%
A change in the path turbulence indicates changed flow
conditions (e.g. a blocked flow conditioner). If the current
turbulence value of any path exceeds the value "Path
turbulence", a User Warning is generated.
The usage of a flow conditioner improves and stabilizes the
flow profile and results in well-defined values for the
turbulence, so that the default value may be applied. In
installations without flow conditioner, the value for the
parameter "Path turbulence" may significantly differ from the
defaults.
When the application is operating under normal conditions,
try to observe, how the Profile factor changes within the
operating range (VOG between Qmin and Qmax).
From these observations reasonable values can be esti-
mated for "Path turbulance" and "Profile factor range".
Off
Signal-to-noise
ratio (SNR)
SNR limit
13 dB
Interfering noise caused by fittings in the pipeline, valves that
are not fully open, sources of noise near the measuring
location, or defective ultrasonic transducers may affect the
SNR. Other possible sources of interference include electrical
noise caused by bad contact of the connectors or sources of
acoustic interference, such as control valves or very high flow
velocities. Typically the SNR is greater than 20dB. It depends
on the nominal diameter of the meter body and the current
process pressure. If the SNR drops below the limit specified in
"SNR limit", a User Warning is generated.
Configure the "SNR limit" to be 6dB below what is
observed in the application under normal operating
conditions.
On
Signal
amplification
AGC limit
93 dB
If the absolute value of the reception gain exceeds the limit
specified as "AGC limit", a User Warning is generated.
Caution:
The current signal amplification largely depends on the current
process pressure (inversely proportional in initial approxima-
tion, that is, if the pressure doubles, the required reception
sensitivity will be halved).
Configure the "AGC limit" to be 6dB below what is observed
in the application at the lowest operating pressure.
On
AGC deviation
10 dB
The absolute difference between both path gain factors is
monitored. If the AGCs of a path deviate more than permitted,
this can indicate a malfunction in the ultrasonic transducers,
electronic modules, transducer cables or parameter settings
(signal models, control limits). If the value specified for the
parameter "AGC deviation" is exceeded by a path, a User
Warning is generated.
Caution:
High flow velocities may also increase the difference in gain.
Considering the application conditions, the "AGC
deviation" may be set to a lower value.
On
2
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pathi
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path
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