Emerson Rosemount 5408 Reference Manual page 106

Service and Troubleshooting
Table 7-6: Incorrect Level Readings
(1)
Symptom
When the product surface is near the slop-
ed tank bottom, the transmitter enters
alarm mode.
(1)
= actual level
Table 7-7: Troubleshooting the 4-20 mA/HART Output
Symptom
Transmitter milliamp reading is zero.
Transmitter milliamp reading is too low or high.
Milliamp reading is erratic.
Transmitter will not respond to changes in level.
96
(continued)
Possible causes
Reduction of projected sur-
face area close to sloping
tank bottom.
Time
= reported level
Recommended actions
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Recommended actions
• Verify the tank geometry parameters
are configured correctly (especially the
Reference Height and Bottom Offset).
• If measurement in this region is not
crucial, increase the Empty Tank Detec-
tion Area, see
• Verify the Bottom echo visible when
tank is empty parameter is disabled,
see
Enable bottom echo visible when tank is
empty.
Verify power is applied to signal terminals.
Verify power supply voltage is adequate at signal terminals,
see Section 4.4.
Verify transmitter and power supply are properly grounded.
Verify level.
Check the settings of the 4-20 mA range values, see
Upper/lower range value.
Verify output is not in alarm condition.
Check that power wires are connected to the correct signal
terminals.
Perform Calibrate Analog Out, see
Verify power supply voltage is adequate at signal terminals,
see Section 4.4.
Check for external electrical interference.
Verify transmitter is properly grounded.
Verify shield for twisted pair is only grounded at the power
supply end.
Under turbulent conditions with low level rates, consider in-
creasing the Damping value.
Verify level is between the 4 and 20 mA set points.
Verify output is not in alarm condition.
Verify transmitter is not in loop test or simulation mode.
Empty tank handling.
Section 7.4.5.
Reference Manual