Allen-Bradley CompactLogix Error Code 16#00A2

Allen-Bradley PLC & VFD Major I/O

Model: CompactLogix | Code: 16#00A2

Applicable Systems

MicroLogix CompactLogix ControlLogix PowerFlex

Symptoms

A remote I/O module has reported a connection loss. The controller logs an I/O connection timeout and the affected module status LED flashes red.

Step 1: Check the I/O adapter status LED for power and network indication
If the power LED is off, check the 24V DC supply to the adapter
Step 2: Inspect the network cable between the controller and the I/O adapter
Replace damaged cables; verify continuity with a cable tester
Step 3: Reseat the I/O module in the rack or DIN rail
Remove and reinsert the module ensuring the connector engages fully
Step 4: If the module status LED remains red after reseating, reflash the firmware
If the fault persists, the module hardware is defective and needs replacement

Reset: The I/O connection restores automatically once communication is re-established. Clear the fault in the controller diagnostic buffer.

I/O module: 8-channel digital input or output (Match to existing rack type and voltage)
Field wiring cable: Shielded, 18 AWG or larger (Use continuous runs without splices)
I/O adapter power supply: 24V DC, 2.5A minimum (Calculate total module current requirement)

Q: How many I/O modules can I have on one network?
Depends on the protocol and controller. EtherNet/IP: 128+ devices. DeviceNet: 64. Check the manual for specific limits.
Q: What is the I/O response time?
Depends on network type and RPI (Requested Packet Interval). Typical: 1-10ms for EtherNet/IP, 5-20ms for DeviceNet.
Q: How do I calculate I/O power requirements?
Sum the current draw of all modules on the adapter. Include a 25% safety margin. If the total exceeds the supply rating, add additional power supplies.