Opening an old SFC project in GX Works3: check versions and the converted chart

During PLC project migration, it is easy to overlook whether the chart remains complete even though program text survives. For an old SFC project, the absence of a software error does not make the converted project ready for site use. This article cites a Mitsubishi technical bulletin with a defined version range and provides offline checks suitable for repair handover.

Start with the bulletin's applicability

FA-A-0192-A, revised in January 2016, concerns GX Works3 versions 1.015R through 1.019V opening GX Works2-format MELSAP3/MELSAP-L programs. Blocks with multiple initial steps may be deleted, and charts containing jumps may return to their initial state. The bulletin recommends version 1.020W or later. This is a specific historical-version issue, not a defect to attribute to every GX Works3 version.

Prepare three records for migration

The first is an archive of the original project and supporting files. The second records the software environment: source software, target software and actual versions. The third inventories the original SFC structure, including block names, initial steps, jump locations and associated actions. That original structure is the comparison baseline; operators' recollection of the display is insufficient.

Convert an offline copy and retain every conversion message. Someone unfamiliar with the original equipment should first ask the design or maintenance lead to explain each chart block. Do not ignore a block simply because its name resembles a spare program.

Sequence of post-conversion checks

1. Check all blocks against the inventory, then initial steps and branch connections; do not prioritize cosmetic formatting.
2. Check jump origins and destinations and match actions and transition conditions in the chart to the original project.
3. Save compilation results and explain every manual change. Keep unexplained differences open as unresolved items.
4. Place before-and-after views and review records in the same delivery directory for independent checking, rather than delivering only the final file.

When on-site validation can begin

A newer software version avoiding a known historical restriction does not complete the entire migration. Target CPU, module configuration and equipment actions require separate confirmation. Site download, trial operation and return to production need an approved plan and recoverable original data. Chart checks here do not replace validation of the machine's safety functions.

If the project is not SFC, or the software version lies outside the bulletin's scope, consult the applicable current product manual instead of copying the old bulletin's corrective methods. For ordinary GX Developer projects, see checks before import into GX Works2. Archive these tasks separately to avoid confusing a version issue with site hardware failure.

Reference: Considerations for opening SFC programs in GX Works2 format with GX Works3, FA-A-0192-A, revision A of January 2016, pages 1–3, applicable software and the two conversion limitations. This text explains scope and suggests ways to organize site records. Follow the documentation for the actual system and machine builder for specific operations.