E2-28

Boot Project Download Error

ABB · AC500-S Safety Controller

What does E2-28 mean?

An error occurred during the download of the boot project to the Safety PLC. This prevents the PLC from loading its operational program correctly and entering a run state, rendering it inoperative.

Common Causes

  • Corrupted boot project file on the engineering workstation or during transfer to the SM560-S Safety PLC's non-volatile memory.
  • Intermittent or unstable communication link (e.g., loose Ethernet cable, network interference) between the engineering workstation and the Safety PLC during the download process.
  • Insufficient free memory or a corrupted memory sector within the Safety PLC's non-volatile memory preventing the boot project from being written correctly.
  • Incompatible boot project version with the current firmware of the SM560-S Safety PLC, leading to a download rejection.
  • Hardware defect in the SM560-S Safety PLC's memory controller or communication interface preventing successful download.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Verify the integrity of the boot project file on the engineering workstation; attempt to download a different, known-good boot project if available.

  2. 2

    2. Replace the Ethernet cable connecting the engineering workstation to the SM560-S Safety PLC's programming port with a known good, certified Cat5e or Cat6 cable.

  3. 3

    3. Perform a power cycle of the SM560-S Safety PLC and retry the boot project download immediately after it restarts.

  4. 4

    4. If the Safety PLC has a removable memory card, replace it with a new, compatible card, then attempt to download the boot project.

  5. 5

    5. Connect to the Safety PLC via engineering software and try to clear its memory (e.g., perform a 'reset to factory settings') before attempting another download.

  6. 6

    6. If repeated attempts fail after all software and hardware checks, replace the SM560-S Safety PLC CPU module.

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Verified technical data. Last updated: March 2026

Related Faults

Source: ABB AC500-S Safety Controller