Overview
Upgrading M580 PLC firmware from version 3.2 to 4.x is not a single-step flash. It requires a two-step procedure — you cannot jump directly from 3.2 to the latest 4.x firmware.
The Two Steps
- Step 1: Flash from firmware 3.2 to an intermediate version (typically the earliest 4.0 release). This establishes the new firmware architecture.
- Step 2: Flash from the intermediate 4.0 version to the target 4.x version. This brings the PLC to the desired firmware level.
Attempting to flash directly from 3.2 to a later 4.x version will fail — the firmware updater will reject the update or the flash will not complete successfully.
Using DDT for Firmware Mismatch
During the migration, you may need to sync programs between controllers running different firmware versions (e.g., primary on 3.2, backup being upgraded). DDT (Device Derived Types) can be configured to allow firmware mismatch, enabling you to transfer or compare programs between controllers that are not yet on the same firmware version.
This is particularly useful in hot standby configurations where you are upgrading one controller at a time.
Procedure
- Back up the current program and configuration from the PLC.
- Download and stage both firmware packages (intermediate and target).
- Ensure you have the Firmware and Data Storage password (required for firmware > 4.0).
- Flash to the intermediate firmware version. Wait for the PLC to restart and verify it boots cleanly.
- Flash to the target 4.x firmware. Wait for restart and verify.
- Download the program (rebuilt for the new firmware version in CE16) and verify I/O and communications.
Do Not Skip Steps
The two-step process exists because the firmware architecture changed between 3.x and 4.x. The intermediate version bridges the two architectures. Skipping it risks bricking the CPU, which would require Schneider RMA to recover.