SIMATIC Panel PC FI15 Backup and S5 PLC Migration Guide

Overview of the SIMATIC Panel PC FI15 Migration Problem

The SIMATIC Panel PC FI15 is a legacy industrial PC from the SIMATIC PC FI series that typically shipped with MS DOS 6.22 or Windows 95, depending on configuration and order code. These units integrated a color display with an industrial PC motherboard, sealed front panel, and 24 VDC power input, and were commonly paired with Siemens S5 PLCs such as the CPU 928B, communicating over PROFIBUS DP through an IM 308 interface module. The FI designation followed the SIMATIC PC naming convention for compact panel-mount industrial PCs.

Because the original FI15 hardware is no longer in serial production and spare LCD panels, inverters, and motherboards are scarce, integrators face three primary engineering tasks when one of these systems fails or its display becomes unreadable:

1. Recover the application from the failing or already-failed storage media (typically an IDE hard disk or, on later units, a CompactFlash card).
2. Identify or replicate the original HMI/SCADA runtime so the S5 PLC program remains operable on the same PROFIBUS segment.
3. Select a replacement panel PC, confirm PROFIBUS DP master capability for continued communication with the S5 CPU 928B, and decide whether to maintain the DOS runtime or migrate the visualization to a modern Windows SCADA.

This reference consolidates the practical procedures used to clone the FI15 hard disk, preserve the PROFIBUS link, and migrate to a current-generation SIMATIC Panel PC. It assumes the S5 PLC, the IM 308 module, and the field wiring remain in service and that only the panel PC is being replaced.

System Identification and Communication Architecture

Before any backup or hardware swap, document the existing architecture in detail. The FI15 was deployed almost exclusively in a single-master PROFIBUS DP configuration with the following components:

• HMI station: SIMATIC PC FI15 with MS DOS 6.22 (most common) or Windows 95, equipped with a CP 5412 (ISA), CP 5611 (PCI), or third-party PROFIBUS interface card. Some installations used a serial RS-232 link with an S5-L2 driver as a lower-cost alternative when PROFIBUS was not required.
• PLC station: SIMATIC S5-135U or S5-155U central rack with a CPU 928B and an IM 308-C DP slave interface module inserted in the rack.
• Bus: PROFIBUS DP segment on shielded twisted-pair cable, RS-485 physical layer, baud rate from 9.6 kbit/s up to 1.5 Mbit/s depending on segment length. Default in most legacy installations was 1.5 Mbit/s for short panels and 187.5 kbit/s when long cable runs connected remote I/O.
• Application: DOS-based process visualization, frequently a ProTool for DOS project, a WinCC flexible early version, or a custom 16-bit DOS executable compiled against an S5 DP library.

Open the FI15 chassis - usually four M4 screws on the rear panel - and record the part numbers on the PROFIBUS card, the CPU type printed on the S5 module faceplate, and the IM 308 order number. The IM 308 order number determines whether it is a DP slave module, a DP master module, or an FMS variant, which directly affects replacement hardware decisions.

Pre-Migration Planning Checklist

Before powering down the FI15, complete the following items to avoid losing PLC visibility or data during the swap window:

Backing Up the FI15 Hard Disk with XCOPY

The most direct method to clone the FI15 storage is the MS DOS XCOPY command. XCOPY copies files, directory structures, and - with the appropriate switches - hidden and system files that comprise the MS DOS 6.22 environment and the HMI application. Unlike a sector-level image, XCOPY is resilient to different destination drive geometries and produces a clean file system on the new medium.

Prerequisites

• A second storage medium of equal or greater capacity. The FI15 was typically delivered with a 540 MB to 2 GB IDE drive. Acceptable targets include a USB-to-IDE bridge with a modern SSD, a CompactFlash-to-IDE adapter with an industrial-grade CF card, or an external USB hard drive pre-formatted with a FAT16 or FAT32 partition. Note that MS DOS 6.22 is limited to FAT16 partitions of up to 2 GB.
• A working PS/2 keyboard attached to the FI15. The front-panel touch overlay cannot be used once the operating system has stopped responding to interrupts, and the USB stack of MS DOS 6.22 has no hot-plug support.
• A bootable MS DOS 6.22 floppy disk, or access to a working MS DOS command prompt via the HMI start menu. If the integrated panel is dead but the VGA port is still functional, connect an external CRT or LCD monitor to the VGA output before powering up.

Procedure

1. Connect the destination drive. If you are using a USB bridge, load the appropriate DOS USB driver stack (e.g., USBASPI.SYS in CONFIG.SYS, or the universal USBDRV package). Many older FI15 systems do not have USB BIOS support, so a direct IDE-to-IDE clone is more reliable. If the FI15 is the CompactFlash variant, the destination can be a second CF card in a USB CF reader.
2. Confirm the destination is partitioned. From the C:\> prompt, run FDISK, create a primary DOS partition using the full available space, set it active, then reboot and run FORMAT D: /S /U to format it as a system volume and copy the DOS system files.
3. At the C:\> prompt, run the XCOPY command:

   xcopy c:\*.* d:\ /E /H /R /S /Y /V

4. Watch the file count and the cumulative bytes. XCOPY displays "n File(s) copied" at the end. Cross-check by running DIR C:\ /A /S and DIR D:\ /A /S on each drive and comparing the totals. A divergence of more than a few kilobytes usually indicates a corrupted source file or a destination write error and warrants a re-run.
5. Once the copy is verified, label the destination drive with the date and source drive serial number, and store it in an anti-static bag.

Switch Reference

Total copy time on a 540 MB drive is typically 8 to 15 minutes on a FI15 with a 486-class CPU, and proportionally less on later units with Pentium-class processors. If the copy is interrupted, simply re-run the same XCOPY command - the /Y switch allows XCOPY to overwrite the partial destination files.

Alternative Backup Methods

For engineers who prefer a graphical interface or a bit-exact clone, two additional methods are commonly used in the field.

PFM (Print/File Manager) for DOS

PFM is a Norton Commander-style shell that provides a two-pane file browser and built-in copy, move, rename, and delete operations. Although the original PFM distribution is no longer hosted by Siemens, copies are preserved in legacy DOS tool archives; the program fits on a single bootable floppy and runs entirely from RAM. To use PFM for the backup:

1. Boot the FI15 from the PFM floppy. If the FI15 does not have a floppy drive, the PFM executable and its overlay can be copied to a small FAT16 partition on the hard disk and launched from there.
2. Select the source partition (C:) in the left pane and the destination (D:) in the right pane by tabbing between panes and using the arrow keys to select drive letters.
3. Press F5 to initiate a copy, then enable the "Include hidden and system files" option in the copy dialog.
4. Confirm the operation. PFM displays a per-file progress bar, which is more legible than XCOPY's scrolling output, and offers a "Verify after copy" toggle that mirrors the /V switch in XCOPY.

Bit-Exact Clone with USB-to-IDE Adapter

For a sector-level copy, remove the FI15 IDE drive, attach it to a modern PC with a USB-to-IDE adapter, and create an image with a tool such as dd (Linux) or HDD Raw Copy Tool (Windows). The resulting .img file can be written back to a CompactFlash card with an IDE-to-CF adapter, or to a SATA SSD with an IDE-to-SATA adapter. This method also captures the master boot record, which is helpful if the HMI relies on a non-standard MBR for dual-booting DOS and Windows 95 on the same drive. The procedure is:

1. Connect the FI15 drive as a secondary drive on a Linux PC. Identify the device with lsblk - it typically appears as /dev/sdb with no partitions, or as /dev/sdb1 if the MBR is recognized.
2. Create the image: sudo dd if=/dev/sdb of=fi15_backup.img bs=4M status=progress conv=noerror,sync. The conv=noerror,sync option continues past read errors, which can occur on aging media.
3. Compress the image: gzip fi15_backup.img. A 540 MB source typically compresses to 80-150 MB because the HMI application and runtime libraries are highly redundant.
4. When needed, write the image back: gunzip -c fi15_backup.img.gz | sudo dd of=/dev/sdc bs=4M status=progress conv=fdatasync, where /dev/sdc is the destination drive.

File System Considerations for the FI15

MS DOS 6.22 supports only the FAT16 file system. The cluster size and maximum partition size depend on the volume size and the DOS version. For the FI15's typical 540 MB to 2 GB drives, FAT16 with 32 KB clusters is the common configuration. When migrating to a larger drive, keep the partition within 2 GB to remain compatible with the original DOS environment. If the HMI application stores large log files, consider configuring a separate FAT16 partition for logs and another for the application.

Long file names are not supported by MS DOS 6.22. The HMI runtime is typically installed under the 8.3 short-name convention (e.g., PROTOOL.EXE, PROJ01.PT1). When copying the application to a modern file system for archival, do not strip the short names; many runtime engines resolve resources by their 8.3 names, not by their long names.

The boot sector of the FI15 drive contains a small DOS bootstrap that loads IO.SYS and MSDOS.SYS, then reads CONFIG.SYS and AUTOEXEC.BAT. These four files are present in the root directory of the cloned drive when the /H switch is used in XCOPY, but a freshly formatted destination will not have IO.SYS and MSDOS.SYS. After the XCOPY, run SYS C: D: to make the destination drive bootable, or simply boot the destination drive from a DOS floppy and run SYS C:.

Preserving the S5 CPU 928B Communication Link

The PROFIBUS link between the replacement HMI station and the S5 CPU 928B passes through the IM 308 module. The IM 308 is a standalone DP slave interface that the S5 CPU accesses through a dual-port RAM mapped into the S5 process I/O area. From the HMI's perspective, communication can be established in two ways.

Option A - HMI as DP Master, S5 as DP Slave

Connect a Siemens CP 5611, CP 5612, CP 5613, or CP 5621 PROFIBUS card to the new Panel PC and configure it as a DP master class 1. Load the IM 308 GSD file into the HMI's PROFIBUS configurator. Assign the I/O addresses to match the original FI15 application. This option is the cleanest migration because the HMI owns the bus and the S5 continues to operate as a slave through the IM 308.

The CP 5611 is a PCI card; the CP 5621 is a PCIe x1 card. For a current-generation SIMATIC Panel PC with an M.2 or PCIe slot, the CP 5621 is the correct choice. For older Panel PCs that retain a PCI slot, the CP 5611 is still available on the second-hand market.

Option B - S5 Retained as DP Master, HMI as a Slave or Monitor

If the original FI15 was a passive bus participant - for example a WinCC or ProTool runtime subscribing to a PROFIBUS FMS connection - the IM 308 remains the master and the new HMI is configured as a slave or as a pure monitoring station. This is rare in DOS-based installations because FMS requires the IM 308-C to be replaced by an IM 308-B or an FMS module, but should be verified by examining the original bus configuration before the swap.

In either case, the PROFIBUS cable shield must be terminated at both ends with the 9-pin D-sub connector providing a 220 Ω termination resistor between pins 3 and 8. The IM 308 ships with the terminator enabled; the last physical node on the bus must also be terminated. The HMI station itself is typically not terminated because it is rarely the last physical node.

Selecting a Replacement Panel PC

Current-generation SIMATIC Panel PCs are listed in the official Siemens product finder at Siemens Panel PC product finder and on the SIMATIC Panel PC overview page. The relevant families for a 1:1 mechanical replacement of a FI15 are the SIMATIC IPC277G, IPC477G, and IPC677G Panel PCs, all of which support PROFIBUS DP via an integrated or plug-in CP 5611-compatible interface.

Selection considerations for a 1:1 mechanical replacement:

• Display size: Match the new panel's diagonal to the existing cabinet cutout, or budget for a new cutout if moving to a larger diagonal. The IPC277G 15" model is the closest direct replacement for a 12" FI15 in a standard control cabinet cutout.
• Touch overlay: A modern projected-capacitive or analog-resistive touch will not work with a DOS application because the touch controller expects a Windows HID driver. Plan for an external keyboard and mouse, or a touch-to-mouse emulation utility, when running the legacy DOS runtime.
• PROFIBUS interface: Choose a model with an accessible PCIe or M.2 slot for the CP 5621 card. The PCI-104 form factor of older FI15 systems is not available on current Panel PCs, so a PCI-104-to-PCIe adapter is required if the original CP 5412 must be retained, and many PCI-104 cards are not supported by current Windows drivers.
• Power supply: 24 VDC input is standard on industrial Panel PCs. Confirm inrush current; a FI15 typically draws 4 to 6 A at 24 V, and the new panel may have a different inrush profile that can trip an undersized cabinet power supply.
• Operating system: Windows 10 IoT Enterprise LTSC 2019 or 2021 is supported on the current SIMATIC IPC families. A DOS emulation layer (e.g., DOSBox-X or vDosPlus) may be required if the original runtime cannot be recompiled against a Windows DP library.

For projects where the S5 must be retired in parallel, the cleanest path is to migrate the visualization to WinCC Unified or TIA Portal WinCC, and replace the S5 with an S7-1500 and an ET 200MP PROFIBUS gateway module. This is a larger project and falls outside the scope of this reference.

Migrating the DOS Application to a Modern OS

If the FI15 ran a custom DOS executable, recompiling it against a Windows-compatible PROFIBUS library is the long-term path. The original DOS code typically called the Siemens PROFIBUS.DLL (16-bit) or accessed the CP 5412 directly through I/O port reads. Two practical paths exist for the migration window:

1. Run the DOS binary inside a DOS emulator. Install DOSBox-X on the new Panel PC, mount the cloned C: drive as a folder, and provide the PROFIBUS interface to the emulated environment by mapping it to a virtual COM port or a network bridge. This preserves the original user interface but is fragile and unsupported for production use. Expect to spend a few hours tuning the cycle rate and the memory configuration to match the original FI15 timing.
2. Replace the HMI with a Windows-based SCADA. This is the long-term path. The S5 CPU 928B can be addressed from WinCC, WinCC Unified, or any OPC UA client through a PROFIBUS-to-OPC gateway such as the Helmholz REX 100 or the Softing PROFIboard. The gateway exposes the S5 process I/O as OPC tags, which the SCADA can read with no further PROFIBUS configuration.

Verification and Commissioning Steps

1. Power the replacement Panel PC from a bench supply and confirm 24 VDC ± 5 % at the input terminals before connecting to the cabinet bus. Verify that the inrush current of the new panel does not trip the cabinet circuit breaker.
2. Boot Windows and verify the CP 5621 is detected in Device Manager with no Code 10 (cannot start) or Code 19 (cannot start, registry problem) errors. The CP 5621 driver is part of the SIMATIC NET PC software suite; install the latest SIMATIC NET release for the operating system in use.
3. Start the PROFIBUS diagnostic tool (e.g., SIMATIC NET PROFIBUS Diagnostics) and confirm the S5 / IM 308 appears on the bus at the expected station address. The tool should show the bus statistics (repeat count, lost tokens, bus errors) within a few seconds of start-up.
4. Trigger a read of each I/O byte that the original FI15 polled. Compare the value to a known process state (e.g., a hand-operated valve or a local input wired to a known state). Confirm data integrity in both directions (HMI to PLC and PLC to HMI).
5. Run the cloned HMI binary in the chosen environment (native Windows after recompilation, or DOSBox-X) and cycle through every screen. Touch inputs must be replaced with mouse clicks if the new panel is a touch model. Verify that operator-acknowledged alarms can be reset and that the audit log records the new panel's user names.
6. Verify the failure behavior of the new panel. Pull the PROFIBUS connector with the system running and confirm that the HMI displays a bus fault and that the S5 CPU does not enter STOP. A correctly configured PROFIBUS slave (the IM 308) should continue to operate the S5 user program even when the master (the HMI) is offline.
7. Document the migration in the plant's asset register. Record the new Panel PC order number, the PROFIBUS card order number, the IM 308 firmware version, the S5 CPU firmware version, and the date the old FI15 was decommissioned. Archive the cloned hard-disk image in a versioned directory on the plant's engineering file server.

Troubleshooting Matrix

Long-Term Considerations and Standards

The PROFIBUS DP standard (IEC 61158 / EN 50170) defines the bus protocol used between the FI15, the IM 308, and any DP slaves. The standard is still maintained by the PROFIBUS user organization, and the protocol layer is identical on current SIMATIC Panel PCs, so a FI15 can be replaced by an IPC477G with a CP 5621 without any change to the bus protocol. The mechanical connector and the bus termination, however, have evolved: the original 9-pin D-sub connector on the FI15 is the same physical connector used on current PROFIBUS nodes, so existing cables and connectors can be retained.

For plants that must remain on PROFIBUS for the foreseeable future, plan the FI15 replacement as the first step in a phased migration to PROFINET. The S5 CPU 928B can be retained with an IE/PB Link PN IO gateway that exposes its process I/O as PROFINET devices, and the new Panel PC can communicate with the S5 through that gateway. This path preserves the S5 investment while providing a clean migration path to PROFINET-based visualization and control.

FAQ