Siemens SITRANS FC430 Operating Instructions Manual page 225

Supply voltage
Warming-up time 30 min.
Cable length
Table 10-3
Current output
Effect of ambient
temperature
Effect of supply
voltage
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
massflow 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.
Incorrect installation of the sensor
● Has the sensor been correctly installed, that is fastened to the floor / wall or frame with
good mounting brackets as shown in the instructions?
Especially for low flowrates, that is flowrates less than 10% of the maximum capacity of the
flow meter, it is important that the sensor is correctly and stably installed.
If the sensor is not correctly fixed in place, the zero point of the sensor will change, leading to
measuring errors.
Try to tighten up the sensor brackets to see whether the flow instability is reduced.
Vibrations and cross talk
Vibrations in the pipe system are normally generated by pumps.
Typically, cross talk is generated by two sensors of identical size and positioned in close
proximity in the same pipe, or installed on the same rail or frame.
FC430 (From firmware 4.0)
Operating Instructions, 06/2017, A5E39789392-AA
Un ± 1 %
5 m between transmitter and sensor
Additions in the event of deviations from reference conditions
As pulse output ± (0.1% of actual flow +0.05 % FSO)
● Display/frequency/pulse output: < ± 0.003%/K act. ± 3.6 °F)
● Current output: < ± 0.005 %/ K act.
< 0.005 % of measuring value on 1 % alteration
Diagnosing and troubleshooting
10.3 Operation troubleshooting
225