Emerson Rosemount 8750W Reference Manual page 168

Troubleshooting
Table 12-12: Test A. Terminal to front electrode
Test conditions
• Location: uninstalled
• Required equipment: Multi-
meter
(1)
• 18 and electrode 18
(1) When the connection head is in the vertical upright position and the flow arrow (see
points to the right, the front of the meter will be facing towards you. Electrode 18 is on the front of the meter. If you cannot determine
the front of the meter, measure both electrodes. One electrode should result in an open reading, while the other electrode should be
less than 0.3 ohm.
Table 12-13: Test B. Terminal to back electrode
Test conditions
• Location: uninstalled
• Required equipment: Multi-
meter
(1)
• 19 and electrode 19
(1) When the connection head is in the vertical upright position and the flow arrow (see
points to the right, the front of the meter will be facing towards you. Electrode 18 is on the front of the meter. If you cannot determine
the front of the meter, measure both electrodes. One electrode should result in an open reading, while the other electrode should be
less than 0.3 ohm.
Table 12-14: Test C. Terminal to reference electrode
Test conditions
• Location: uninstalled
• Required equipment: Multi-
meter
• 17 and process reference
(1)
electrode
(1) Only valid if the sensor has a process reference electrode.
Table 12-15: Test D. Terminal to case ground
Test conditions
• Location: uninstalled
• Required equipment: Multi-
meter
• 17 and safety ground
164
Expected
value Potential cause
≤ 1 Ω
• Shorted electrode
• Open electrode
• Coated electrode
Expected
value Potential cause
≤ 1 Ω
• Shorted electrode
• Open electrode
• Coated electrode
Expected
value Potential cause
≤ 0.3 Ω
• Shorted electrode
• Open electrode
• Coated electrode
Expected
value Potential cause
≤ 0.3 Ω
• Moisture in terminal block
• Leaky electrode
• Process behind liner
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Rosemount 8750W Transmitter with Modbus Protocol Reference Manual
Corrective action
• Replace sensor
• Remove coating from sensor
wall
Section 3.2.3) on the connection head flange
Corrective action
• Replace sensor
• Remove coating from sensor
wall
Section 3.2.3) on the connection head flange
Corrective action
• Replace sensor
• Remove coating from sensor
wall
Corrective action
• Clean terminal block
• Replace terminal block
• Replace sensor