EL
ErrorLib
Brands
||
  1. Home
  2. Mitsubishi Electric
  3. MELSEC System Q/L Series
  4. 1102
About·Privacy·Terms

ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

1102

RAM Error - Work/Standard/Extended RAM

Mitsubishi Electric · MELSEC System Q/L Series

What does 1102 mean?

The work area RAM in the CPU module, or the standard and extended RAM areas, are faulty. This diagnostic occurs at power ON, after a reset, or when an END instruction is executed.

Common Causes

  • Faulty work area RAM in the CPU module.
  • Faulty standard RAM and/or extended RAM in the CPU module.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the incoming supply voltage to the PLC's power supply module and verify it adheres to the specified voltage range.

  2. 2

    Inspect the CPU module to ensure it is correctly and securely seated in its base unit; re-seat the module firmly if any looseness is detected.

  3. 3

    Verify the status of the CPU module's backup battery (if present) using its status indicators, and measure its voltage if safely accessible and within specification.

  4. 4

    Inspect the CPU module, its base unit connector, and the backplane for any signs of physical damage, corrosion, or foreign material.

  5. 5

    Verify that the operating environment's temperature and humidity are within the specified limits for the MELSEC Q/L Series system.

Browse all codes in this manual (53)
Verified technical data. Last updated: April 2026

Related Faults

1000CPU Down Error1001CPU Down Error with Device Access Issue1002CPU Down Error
Source: Mitsubishi Electric MELSEC System Q/L Series
Open Manual (Page 1308)Search more codes in this manual