F940GOT-SWD-E Program Transfer to PC: Mitsubishi GOT-F900 Series Upload Procedure

The Mitsubishi F940GOT-SWD-E is a 5.7-inch monochrome graphic operation terminal from the GOT-F900 series, used as the operator interface for MELSEC FX-series PLCs. When the integrated LCD becomes illegible from backlight failure or panel aging, the project file inside the HMI is typically still intact and recoverable through the RS-232C port using GT Designer software and the FX-232CAB cable. This reference covers the complete upload procedure, screen diagnostics, and restoration to a replacement unit.

F940GOT-SWD-E Hardware Overview

The F940GOT-SWD-E is the 24 VDC-powered variant of the GOT-F940 family. The "SWD" suffix identifies the supply voltage and connector orientation, distinguishing it from the F940GOT-LWD-E (5 VDC variant) and F940GOT-LBD-H (high-performance model).

Software Required for Project Upload

Two software generations support the GOT-F900 series: the legacy GT Designer (Ver.5) and the modern GT Designer2 included in GT Works2. Both can read and write F900 project files (extension .GOT for GT Designer, .GTE for GT Designer2 with F900 module). GT Designer2 is recommended for new installations because it remains available from Mitsubishi Electric's download service and supports Windows 7, 10, and 11 with the appropriate compatibility settings.

Download or order the latest F900-compatible GT Works2 from the Mitsubishi Electric FA global website. The official GOT-F900 Series Graphic Operation Terminal manual (JY992D94801F) documents the upload and download protocols referenced throughout this guide.

Required Cables and Adapters

The PC connects to the F940GOT-SWD-E RS-232C port using a straight-through 9-pin serial cable. Modern PCs without an integrated DB-9 COM port require a USB-to-serial adapter based on the FTDI FT232 or Prolific PL2303 chipset. Mitsubishi officially certifies the F2-232CAB-1 and FX-232CAB-1 cables.

Pinout of the F940GOT-SWD-E RS-232C port (9-pin D-sub, female, panel-front face):

The cable is straight-through (no crossover). Pins 2-3 are not crossed because the F940GOT-SWD-E is a DCE device relative to the PC.

Identifying Your Model and Communication Port

The model code is printed on the rear label. Verify the suffix before connecting:

• F940GOT-SWD-E: 24 VDC supply, monochrome, English firmware. The standard variant covered by this guide.
• F940GOT-LWD-E: 5 VDC supply (legacy), otherwise identical panel and software.
• F940GOT-SBD-H: High-performance variant with expanded memory (1 MB), color support, and additional protocols. Uses different part numbers for the backlight and cassette but the upload procedure is identical.
• F940GOT-SWD-E (K): Export-restricted variant with limited communication drivers.

The RS-232C port is on the front face of the unit behind a small rubber flap at the bottom right. Do not confuse it with the RS-422 port (8-pin mini-DIN) on the bottom edge, which connects to the FX PLC.

Pre-Upload Verification

Before initiating the upload, complete these checks to avoid mid-transfer failures that could corrupt the project file inside the F940GOT.

1. Power supply check: Confirm 24 VDC at the GOT terminals (24V, 0V). Voltage below 21 V (the -15% limit) will cause the upload protocol to abort with a checksum error at 30-60% completion.
2. CPU load check: If the GOT is connected to a running FX PLC, leave the PLC in RUN. The GOT-F900 upload protocol does not require a PLC stop; it reads directly from the GOT memory.
3. PLC RS-422 cable: Disconnect the FX-422CAB cable from the GOT bottom port during the upload. Some early F940 firmware versions misinterpret RS-422 traffic on adjacent pins as a bus collision and abort the session.
4. PC COM port test: Use a loopback connector or a terminal emulator (e.g., PuTTY) to confirm the COM port transmits at 9,600 bps with no overrun errors before launching GT Designer.
5. Memory cassette status: If an FX-EEPROM-4C, FX-EEPROM-8C, or FX-RAM-32C is installed, the upload reads from the cassette first if the project is set to "Boot from cassette." Check the original project on the PLC integrator's documentation.

Step-by-Step Upload Procedure to PC

This procedure assumes the F940GOT-SWD-E screen is unreadable. No interaction with the HMI screen is required because the upload command is initiated from the PC. The F940GOT automatically enters transfer mode when it receives the GOT900 protocol handshake on the RS-232C port.

1. Open GT Designer2 and select File > New Project. In the GOT type selector, choose F940GOT-SWD-E. Click OK. A blank project opens.
2. Configure the COM port via Communication > Transfer Setup. Select RS-232C, the PC COM port (e.g., COM3), and 9,600 bps. Set transfer mode to Upload (Read from GOT).
3. Apply 24 VDC to the F940GOT-SWD-E. Wait approximately 5 seconds for the boot sequence. The unit performs a self-test; even with an unreadable LCD, the power LED illuminates and internal relays click.
4. Connect the FX-232CAB-1 between the PC and the F940GOT RS-232C port. Tighten the connector screws.
5. Click Read in the Transfer Setup dialog. GT Designer2 issues a GOT900 protocol handshake. The status bar reports Connecting... for 2 to 4 seconds, then Reading....
6. Monitor the progress bar. A 256 KB project transfers in roughly 45 to 90 seconds at 9,600 bps. The 19,200 bps option (if available in the menu) cuts this to 25 to 40 seconds.
7. Save the project when the dialog confirms Transfer completed. Use File > Save As, change the type to GOT-F900 Project (*.GTE), and store the file with a meaningful name including the date.
8. Verify the project by clicking Tool > Verify or by re-reading the GOT and comparing checksums. The read-back checksum must match the just-uploaded file's checksum.

Recovering From a Memory Cassette

If the F940GOT-SWD-E contains an FX-EEPROM-4C, FX-EEPROM-8C, or FX-RAM-32C memory cassette and the internal flash is suspected to be corrupted, the cassette can be moved to the replacement unit and read directly.

1. Power down both the old and the new F940GOT-SWD-E.
2. Open the cassette cover on the rear of the failed unit (two screws, captive).
3. Press the cassette eject lever; the FX-EEPROM or FX-RAM cassette slides out on its connector.
4. Inspect the cassette PCB for capacitor leakage or oxidation. Clean the gold-finger contacts with isopropyl alcohol if contamination is visible.
5. Insert the cassette into the new F940GOT-SWD-E in the same orientation. The label faces up.
6. Power the new unit. The boot sequence detects the cassette and prompts to boot from it (if the original project had this option enabled).
7. Use the procedure above to upload the project from the new unit to the PC for archival.

The FX-RAM-32C cassette requires a battery to retain data. If the cassette has been without power for more than 30 days, the project may be lost. FX-EEPROM-4C and FX-EEPROM-8C retain data for 10+ years without power.

Restoring the Project to a Replacement F940GOT-SWD-E

With the project archived on the PC, transfer it to the new unit that the user has already ordered.

1. Apply 24 VDC to the new F940GOT-SWD-E. Confirm the unit boots (front-panel LED indicator).
2. Connect the FX-232CAB-1 cable between the PC COM port and the new unit's RS-232C port.
3. In GT Designer2, open the archived .GTE file.
4. Select Communication > Transfer Setup. Choose RS-232C, the correct COM port, 9,600 bps, and transfer mode Download (Write to GOT).
5. Click Write. The new F940GOT-SWD-E enters transfer mode automatically and accepts the project. Progress takes 45 to 90 seconds for a typical 256 KB screen set.
6. After the download completes, cycle power to the new GOT. The new unit displays the previously unreadable project on a fresh LCD.
7. Connect the RS-422 cable (FX-422CAB) between the new GOT and the FX PLC. Verify communication by toggling a bit in the PLC and confirming the corresponding indicator changes on the HMI.

Diagnosing an Illegible LCD

An unreadable screen does not necessarily mean the project inside the GOT is lost. The F940GOT-SWD-E has several distinct failure modes that produce a blank or distorted display while leaving the internal flash memory intact.

To access the contrast setting without seeing the screen, the F940GOT-SWD-E responds to the following key sequence on the touch panel during boot: press and hold the upper-left cell (cell 1,1) for 5 seconds while applying 24 VDC. The System Menu appears with contrast slider controllable via the touch panel.

If the touch panel is also unresponsive, the only reliable method is the PC upload procedure detailed above. The serial protocol does not depend on the LCD or touch panel state.

Communication Parameters

The default GOT-F900 RS-232C settings must match between the GOT and GT Designer2:

If the upload fails with Communication timeout, the most common cause is mismatched flow control. Set both sides to None first; this works on every F940GOT variant. If the upload still times out, switch to Xon/Xoff.

Troubleshooting Matrix

Verifying the Recovered Project

After uploading, perform three verification steps to confirm the project is fully intact and functionally equivalent to the original.

1. Checksum verification: In GT Designer2, open the recovered .GTE file and select Tool > Project Information. Note the file checksum. Compare with a second upload (re-read from GOT if still available) or with the original integrator's documentation.
2. Screen enumeration: Confirm the screen count matches expected. A typical F940GOT project has 10 to 50 base screens and 50 to 200 overlay screens. Missing screens indicate incomplete upload.
3. PLC tag cross-reference: Select Tool > Cross Reference to enumerate every PLC device (X, Y, M, D, T, C) referenced by the HMI. Cross-check against the FX PLC program to confirm all referenced devices exist and are correctly addressed.

Preventive Measures for Future Recoveries

Once the project is recovered to the PC, archive it in three locations to prevent future loss.

• PC hard drive: Store the .GTE file in a project-specific folder. Add the original screen capture PDFs if available.
• FX-EEPROM-8C cassette: Re-write the cassette with the recovered project. The cassette provides a hardware backup that survives PLC and HMI failures.
• Network share or cloud storage: Synchronize the .GTE file to a controlled-access location. Tag with the project name, machine serial number, and last revision date.

Schedule a quarterly read-back from the production HMI to PC and compare checksums. Any drift indicates flash wear or unauthorized edits.

Related Documentation

Refer to the official Mitsubishi Electric GOT-F900 Series Graphic Operation Terminal manual (JY992D94801F) for the complete command set, error codes, and protocol specifications. The manual covers RS-232C and RS-422 pin assignments, the GOT900 transfer protocol, and the System Menu structure referenced in this guide.