GE/Emerson PACSystems RX3i — Fault Tables & Recovery

GE · intermediate · 30 min

A PACSystems RX3i logs faults in two tables — Controller and I/O. Read them in Proficy Machine Edition to find the exact cause (a lost I/O module, a PROFINET device), fix it, then clear the tables.

ℹ️ The RX3i keeps a Controller Fault Table and an I/O Fault Table. Read both in PME before clearing — the entry names the rack/slot (and for PROFINET, the remote device) so you know exactly where to look.

Two fault tables

On a GE / Emerson PACSystems RX3i CPU, faults are recorded in two fault tables:

• Controller Fault Table — CPU-level and system faults (e.g. a LAN system-software fault, configuration or system events).
• I/O Fault Table — faults on the I/O system, such as a loss of an I/O module or a remote device fault.

Reading both is the first step — the table entry tells you the fault type, the location (rack/slot), and a timestamp.

Read the tables in Proficy Machine Edition

1. Go online with Proficy Machine Edition (PME) to the RX3i CPU.
2. Open the Controller Fault Table and the I/O Fault Table. Each entry names the fault and where it occurred.
3. Locate the fault:

• A loss of I/O module entry names the rack/slot — check that module's presence, seating, and power.
• For remote PROFINET IO faults, RX3i firmware 9.40 or later identifies the fault uniquely by Remote Rack, Remote Slot, Remote Sub-Slot, and Device ID, so you can pinpoint the exact remote device and slot.

Fix the cause

• Lost I/O module: reseat or replace the module named in the I/O Fault Table; confirm its power and that it matches the configured module.
• PROFINET remote device: using the Remote Rack/Slot/Sub-Slot/Device ID, check that remote device's network connection, power, and configuration.
• Controller/LAN fault: address the system condition the Controller Fault Table names (network, configuration, or a recoverable system-software fault).

Clear the fault tables

Once the cause is resolved, clear the Controller Fault Table and I/O Fault Table in PME. Clearing removes the logged entries; if a fault is still active, it re-logs immediately, which tells you the cause isn't fixed.

Fault handling in logic

For faults you want the application to handle rather than just log, PACSystems supports Fault Handling and Diagnostic Logic Blocks (described in the CPU Programmer's Reference) — use these to detect and respond to specific faults in the program instead of relying on manual clearing.

Step-by-step

1. PME online → open the Controller and I/O Fault Tables.
2. Read the entry — type, location (rack/slot, or PROFINET remote identifiers on fw 9.40+).
3. Fix the cause — reseat/replace the lost module, restore the PROFINET device, or resolve the controller/LAN condition.
4. Clear both fault tables in PME.
5. Verify the tables stay clear and the CPU runs; a re-logged entry means the cause persists.

Verify

After clearing, confirm no new entries appear and the CPU is in RUN with I/O healthy. A fault that re-logs immediately is still active — go back to the named rack/slot or PROFINET device.