Emerson Rosemount 5408, Справочное руководство

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Table 7-6: Incorrect Level Readings
(continued)
Symptom
(1)
Possible causes Recommended actions
When the product surface is near the
sloped tank bottom, the transmitter enters
alarm mode.
Level
Time
Reduction of projected
surface area close to sloping
tank bottom. • 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
Detection Area, see
Empty tank
handling .
• Verify the Bottom echo visible when
tank is empty parameter is disabled,
see
Enable bottom echo visible when
tank is empty .
(1) = actual level = reported level
7.3.2 Troubleshooting the 4-20 mA/HART
®
Output
Table 7-7: Troubleshooting the 4-20 mA/HART Output
Symptom Recommended actions
Transmitter milliamp reading is zero. • Verify power is applied to signal terminals.
• Verify power supply voltage is adequate at signal terminals,
see
Power supply .
• Verify transmitter and power supply are properly grounded.
Transmitter milliamp reading is too low or high. • 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 Calibrate analog out .
Milliamp reading is erratic. • Verify power supply voltage is adequate at signal terminals,
see
Power supply .
• 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
increasing the Damping value.
Service and troubleshooting Reference Manual
February 2020 00809-0100-4408
112 Reference Manual