Troubleshooting/FAQs
9.2 Diagnosing with PDM
SITRANS FUS080 transmitter
Operating Instructions, 07/2012, A5E03059912-02
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Gain step error conditions
Condition Cause
15
No transducer (e.g. defective cable)
Empty pipe
High values
High damping (e.g. inhomogeneous media)
Unsuitable medium
Path angular misalignment
Unstable/fluctuating values
Air bubbles or solids in medium
Bad inlet conditions
Δ gain step between path 1 and path 2 > 1
(2-path systems only)
Bad inlet conditions
Inhomogeneous medium
Path angular misalignment
In case of angular misalignment between transducer faces, the gain step will increase as
shown in the table below:
Angular misalignment Gain step increase
2° 1
3° 2
4° 3
5° 5
Flow velocity error conditions
Condition Cause
Δ flow velocity values (between path 1 and path
2) > 1
(2-path systems only)
Bad inlet conditions (the higher the delta, the
worse the inlet conditions)
Disturbances in the pipe (bad flow profile)
Unstable/fluctuating values
Air bubbles or solids in media
Bad inlet conditions
The actual velocities for the paths should be stable, constant and smoothly changing values
between 0 and 10 m/s.