Mitsubishi GX Works3 and GX Works2

Mitsubishi Electric PLCs (MELSEC) are programmed with the MELSOFT software family. GX Works3 is the current tool for the newest PLCs; GX Works2 and the older GX Developer are still everywhere on existing machines.

Which version for which PLC?

They are part of the MELSOFT iQ Works suite, along with GT Designer3 for GOT HMIs and MR Configurator2 for servos.

Devices (addresses)

FX PLCs number X and Y in octal (X0–X7, X10–X17); Q and iQ-R use hexadecimal. See PLC addressing.

Writing ladder

• F5 / F6 place NO / NC contacts, F7 a coil, F8 an application instruction, Shift+F7 / Shift+F8 rising / falling pulse contacts, F9 a horizontal line, Shift+F9 (or the vertical line tool) a vertical line.
• After editing, the rung is grey until you Convert (F4). Only converted ladder can be written to the PLC.
• Timers take a constant: OUT T0 K30 means 30 × 100 ms = 3 s on a 100 ms timer.
• Device comments (names) are stored separately and shown under each contact.

Languages: ladder, ST, FBD/LD and SFC. See PLC programming languages.

Online

1. Set the connection (USB or Ethernet) under "Specify Connection Destination".
2. Write to PLC: select program, parameters and comments.
3. Put the PLC in RUN (switch or remote RUN).
4. Monitor mode shows contacts and coils live; the device monitor shows a block of registers. Online program change lets you edit while running (carefully).

Both GX Works2 and GX Works3 have a built-in simulator, so you can test without a PLC.

Tips

• Use the cross-reference to find double coils; GX Works checks for them when you run the program check.
• Use labels (global and local) in GX Works3 to write portable, readable programs.

Switch the PLC Sim Lab Playground to Mitsubishi to see your program with X/Y addresses and GX-style F-keys.