Siemens SITRANS FC330, Руководство по эксплуатации, Страница: 192 / 280

FSO (sensors
max. flow rate)
Error in % of actual mass flow rate with 95% confidence
(probability)
Actual mass
flow rate
-1.0
-0.5
1.0
0.5
0.15
-0.15
50% 25% 5% 75% 100%
Table 10-1 Reference conditions for flow calibrations (ISO 9104 and DIN/EN 29104)
Flow conditions Fully developed flow profile
Temperature,
medium
20 °C ± 2 °C (68 °F ± 3.6 °F)
Temperature,
ambient
20 °C ± 2 °C (68 °F ± 3.6 °F)
Liquid pressure 2 ± 1 bar
Density
0.997 g/cm3
Brix 40 °Brix
Supply voltage Un ± 1 %
Warming-up time 30 min.
Cable length
5 m between transmitter and sensor
Table 10-2 Additions in the event of deviations from reference conditions
Current output As pulse output ± (0.1% of actual flow +0.05 % FSO)
Effect of ambient
temperature
● Display/frequency/pulse output: < ± 0.003%/K act. ± 3.6 °F)
● Current output: < ± 0.005 %/ K act.
Effect of supply
voltage
< 0.005 % of measuring value on 1 % alteration
Step 4: Improving the application
In the following it is described how to find the causes of a high Zero point standard deviation and
how to improve the installation.
Setting Low flow cut-off
In order to see if the zero point becomes more stable when making changes / adjustments, the
Low Mass flow cut-off (MassFlowCutOff) must be set to 0.0 kg/s.
When Low flow cut-off has been set, it is possible to see the instability directly from the mass
flow in the online window ("View → Process variables")
This information can be used to troubleshoot. For example, tightening the brackets which hold
the sensor, or turning off the pump to check if vibrations from the pump are disturbing the
sensor, etc.
Diagnostics and troubleshooting
10.3 Operation troubleshooting
SITRANS FC330
192
Operating Instructions, 01/2019, A5E44030648-AB