Flash Read Error

What does 8460 mean?

An error was detected while the Safety PLC attempted to read data from its internal flash memory. This often indicates corruption of the stored firmware, configuration, or boot project, or a hardware defect in the flash memory itself. This can prevent the PLC from booting up, loading its program, or maintaining persistent data, risking system failure.

• Corruption of the stored firmware image, boot project, or configuration data in the internal flash memory.
• Hardware defect of the flash memory chip itself within the safety PLC.
• Power supply interruption or instability during a flash write operation, leading to data corruption.
• Excessive write cycles to the flash memory (less common in PLCs but possible with frequent logging/updates) causing wear.

Click steps to track your progress.

1. 1

   Perform a power cycle of the safety PLC by removing and reapplying the 24VDC supply voltage at terminals L+ and M.

2. 2

   Attempt to re-download the safety PLC's firmware image using the appropriate manufacturer's tool (e.g., TIA Portal Firmware Update tool).

3. 3

   Execute a full memory reset (e.g., "MRES") on the safety PLC to clear any corrupted data, then attempt to download the entire safety project.

4. 4

   Verify the stability of the 24VDC power supply to the safety PLC, checking for voltage fluctuations or drops.

5. 5

   If an SD card is used for boot-up or firmware, replace it with a new, tested card and re-download relevant files.

6. 6

   Replace the safety PLC CPU module if the flash read error persists after attempting firmware re-download and memory reset.