Siemens SITRANS F US SONOKIT, Operating Instructions Manual, Page: 61 / 95

Troubleshooting/FAQs
9.2 Diagnosing with PDM
SITRANS FUS080 transmitter
Operating Instructions, 07/2012, A5E03059912-02
59
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.