The FX3U-CF-ADP is Mitsubishi Electric’s CompactFlash card interface adapter for the MELSEC FX3U compact PLC series, providing removable CompactFlash memory card connectivity for large-capacity data logging, recipe storage, program backup, and file-based data exchange between the FX3U controller and PC-based production management systems — enabling the FX3U to read and write structured data files on a standard CompactFlash card for offline analysis, batch record keeping, and factory-wide data distribution without requiring a network connection. As the FX3U platform’s solution for high-volume data persistence beyond internal device memory capacity, the FX3U-CF-ADP bridges the gap between the compact PLC’s internal data storage and the large-capacity, transferable storage needed for production data historians and recipe management systems. The FX3U-CF-ADP is available through Atlantech Drives — quote within 24-48 hours, worldwide express shipping, 12-month warranty.
What Is the FX3U-CF-ADP?
The FX3U-CF-ADP is a MELSEC FX3U series left-side special adapter module providing a Type I/II CompactFlash card slot for reading and writing data files on a standard CompactFlash card from within the FX3U CPU program. The adapter connects to the FX3U base unit’s left-side special adapter interface and presents a file-based storage interface to the FX3U CPU — the ladder program uses dedicated CompactFlash file instructions (CF_OPEN, CF_READ, CF_WRITE, CF_CLOSE) to create, read, and write CSV-format data files on the CompactFlash card, with the file operations executed by the adapter’s internal processor asynchronously from the FX3U CPU scan. The CompactFlash card is accessible from any PC’s card reader slot, enabling downloaded production records to be imported directly into spreadsheet applications or database systems without requiring network connectivity. The adapter supports CompactFlash cards from 32 MB to 2 GB capacity — sufficient for millions of production records, thousands of recipe parameter sets, or complete FX3U program backups.
Key Technical Specifications
- Model: FX3U-CF-ADP
- Interface: CompactFlash Type I/II card slot
- Supported Card Capacity: 32 MB to 2 GB (FAT16/FAT32 format)
- Connection Interface: FX3U left-side special adapter bus
- File Format: CSV (comma-separated values), binary for program backup
- File Operations: Open, read, write, close, delete, directory listing
- Maximum Files per Directory: 512
- Data Transfer Rate: Approx. 100 KB/s (write), 500 KB/s (read)
- Card Insertion/Removal: Hot-swap supported (with file close confirmation)
- Card Access Indicator: LED (green = ready, flashing = accessing)
- Current Consumption (adapter bus): 0.10 A at 5 VDC
- Operating Temperature: 0°C to 55°C
- Weight: Approx. 0.10 kg
Series Comparison & Selection Guide
The FX3U platform offers two approaches to large-capacity data storage: the FX3U-CF-ADP CompactFlash adapter and the FX3U-FLROM-1M internal flash ROM expansion. The FX3U-CF-ADP is the correct choice when data must be physically transferred between the machine and a PC system — the CompactFlash card can be removed from the adapter and inserted directly into a PC card reader, providing a physical data transfer medium that does not require network connectivity. This is particularly valuable in environments where machine network connectivity is unavailable, restricted by IT security policy, or where batch data collection (end-of-shift production reports, daily quality records) is preferred over continuous network logging. The FX3U-FLROM-1M provides 1 MB of additional non-volatile program and data memory within the FX3U base unit but cannot be removed for data transfer — its data is accessible only via the FX3U’s RS-422 or optional Ethernet interface. For applications requiring both large removable data storage (FX3U-CF-ADP) and expanded program memory (FX3U-FLROM-1M), both can be installed simultaneously on the FX3U left-side adapter bus, occupying two of the four available adapter positions. Comparing the FX3U-CF-ADP to the MELSEC-Q QJ71MES96N MES interface module: the FX3U-CF-ADP provides physical removable storage without network infrastructure, while the QJ71MES96N provides real-time database connectivity requiring an Ethernet network to a database server. For FX3U systems, the CF-ADP is the more practical data logging solution; for MELSEC-Q systems with existing IT infrastructure, the QJ71MES96N provides more sophisticated data management.
Maintenance Tips
CompactFlash cards used in industrial applications with high write cycle rates (continuous data logging at high frequency) have a finite write endurance determined by the flash memory’s program/erase cycle rating — industrial-grade CompactFlash cards (rated for 1–5 million write cycles per block) should be specified rather than consumer-grade cards (rated for 100,000 cycles). Monitor the available free space on the CompactFlash card via the FX3U program’s card status register — schedule regular card archiving and formatting procedures when free space drops below 20% of total capacity to prevent file system fragmentation from degrading write performance. For high-frequency logging applications (more than 1 write per second continuously), structure the data logging as periodic bulk writes (write 100 records to the card every 100 seconds) rather than individual writes per record (100 individual writes per 100 seconds) — bulk writes reduce the number of file open/close cycles and significantly extend card life by reducing the wear on the file allocation table sectors, which are rewritten on every file open/close operation. When replacing a worn CompactFlash card, format the new card in FAT32 format on a PC before inserting it into the FX3U-CF-ADP — the adapter creates the required directory structure on first access, but starting with a clean formatted card eliminates the risk of residual file system data from previous use causing directory errors. Always close all open files via the CF_CLOSE instruction in the FX3U program before removing the CompactFlash card — removing the card with an open write file causes incomplete file writing and potential file system corruption that may require reformatting the card to resolve.
Frequently Asked Questions
Q: Can the FX3U-CF-ADP be used to backup and restore the complete FX3U program including device data?
A: Yes. The FX3U-CF-ADP supports full program backup to CompactFlash card via a dedicated backup operation initiated from the FX3U system’s parameter settings in GX Works2 or via a dedicated backup instruction in the FX3U ladder program. The backup writes the complete program, parameters, and optionally the current device data (D registers, M relays) to a binary backup file on the CompactFlash card. Restoration from the backup file is performed by inserting the backup card and initiating a restore operation — enabling rapid replacement of a failed FX3U base unit with a new unit restored from the backup card without requiring a PC with GX Works2 on-site.
Q: What CompactFlash card brands are compatible with the FX3U-CF-ADP?
A: The FX3U-CF-ADP is compatible with standard CompactFlash Type I and Type II cards from most major manufacturers (SanDisk, Transcend, Innodisk, ATP) formatted in FAT16 or FAT32. Mitsubishi recommends using industrial-grade CompactFlash cards with extended temperature ratings (-40°C to +85°C) for reliable operation in industrial cabinet environments, and cards with a write protect switch for read-only data distribution applications. SDXC-to-CF adapters and microSD-to-CF adapters are generally not recommended as their internal protocol conversion can cause timing incompatibilities with the FX3U-CF-ADP’s file access instructions.
Q: Can the FX3U-CF-ADP be hot-swapped while the FX3U is running?
A: Yes, but only after confirming that no file operations are in progress. The FX3U-CF-ADP supports hot card removal — the CompactFlash card can be removed and inserted while the FX3U is powered on and running. Before removing the card, verify that the access LED is not flashing (indicating active file I/O) and execute CF_CLOSE to close any open files. Removing the card while a file write is in progress will corrupt the open file and may corrupt adjacent directory entries on the card, potentially causing loss of recently logged data.
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