Emerson Rosemount OCX8800A - Page 219

Potential cause
Loose or open O
2
cell circuit connection.
Recommended actions
1. Check O
2
cell circuit wires for breaks or loose connections.
2. Repair lead wire breaks or loose connections.
Potential cause
O
2
cell degraded or failed.
Recommended action
Check O
2
cell impedance by reading the O2 Cell Imped value via the local
operator interface (LOI) (see Figure 4-4) or the O2 Snsr R value via HART
®
(see
Figure 5-3).
• If cell impedance is zero, replace O
2
cell with cell replacement kit.
• If cell impedance is less than 5000 ohms, check for cell housing ground
fault. Repair ground fault.
• If cell impedance is greater than 5000 ohms and no ground fault is
indicated, replace O
2
cell with cell replacement kit.
9.3.2 Ref Current Err
Resistance temperature device (RTD) excitation current error. Reference current
should be 5.02 mA.
Potential cause
Loose or open lead or circuit wire connection for COe sensor or cold junction
connector (CJC) sensor current loop.
Recommended actions
1. Check all COe and CJC sensor current loop wiring per Figure 9-2 and
Figure 10-9.
2. Correct wiring faults.
Potential cause
COe sensor grounded.
Recommended actions
1. Check resistance of COe sensor leads to ground per Figure 10-9.
2. Replace COe sensor if resistance is less than 10M ohms.
Potential cause
COe sensor failed.
Recommended actions
1. Check resistance of both COe sensor elements per Figure 10-9.
Manual
Troubleshoot
00809-0500-4880 December 2022
Rosemount OCX8800A 219