Siemens SITRANS FUS080 Operating Instructions Manual page 61

Gain step error conditions
Condition
15
High values
Unstable/fluctuating values
Δ gain step between path 1 and path 2 > 1
(2-path systems only)
In case of angular misalignment between transducer faces, the gain step will increase as
shown in the table below:
Angular misalignment
2°
3°
4°
5°
Flow velocity error conditions
Condition
Δ flow velocity values (between path 1 and path
2) > 1
(2-path systems only)
Unstable/fluctuating values
The actual velocities for the paths should be stable, constant and smoothly changing values
between 0 and 10 m/s.
SITRANS FUS080 transmitter
Operating Instructions, 07/2012, A5E03059912-02
9.2 Diagnosing with PDM
Cause
No transducer (e.g. defective cable)

Empty pipe

High damping (e.g. inhomogeneous media)

Unsuitable medium

Path angular misalignment

Air bubbles or solids in medium

Bad inlet conditions

Bad inlet conditions

Inhomogeneous medium

Path angular misalignment

Gain step increase
1
2
3
5
Cause
Bad inlet conditions (the higher the delta, the

worse the inlet conditions)
Disturbances in the pipe (bad flow profile)

Air bubbles or solids in media

Bad inlet conditions

Troubleshooting/FAQs
59