Upload Program from SIMATIC C7-623/P: STEP 7 Procedure

The SIMATIC C7-623/P is a compact control system that integrates a SIMATIC S7-300 CPU and an operator panel (OP) into a single device. Uploading the program from the device to a programming device (PG/PC) is a routine commissioning and service task, but the procedure differs from a standard S7-300 CPU because the C7-623/P must be addressed through the standard STEP 7 "Accessible Nodes" path, and the operator panel portion must be handled with the matching ProTool or ProTool/Lite toolchain. This article documents the complete upload workflow, the firmware and tool-version constraints that determine whether the upload is possible at all, and the verification checks that confirm a successful transfer.

1. System Overview and Upload Paths

The C7-623/P is documented in the official Siemens manual SIMATIC C7-623, C7-624 Control Systems, Volume 2. The device combines the following logical components in a single housing:

The MPI port serves both the CPU side and the OP side. An upload therefore returns two distinct artifacts:

• A STEP 7 project containing the PLC program (OB, FB, FC, DB, SDB, system data).
• A ProTool project (or a ProSave backup image) containing the HMI screens, text lists, alarm logs, and recipes.

Both artifacts must be retained together to fully reconstruct the machine's runtime behavior. Uploading only the PLC program leaves the panel showing a default or blank configuration.

2. Prerequisites

2.1 Software

• STEP 7 V5.x (V5.3, V5.4, or V5.5) installed with SP/K updates. STEP 7 V5.5 is the most recent Classic release and is the preferred choice for older C7 devices, but if the C7-623/P CPU is on very early firmware the older V5.3/V5.4 toolchain is required because newer STEP 7 service packs drop the older CPU firmware entries from the hardware catalog.
• ProTool / ProTool/Lite matching the panel firmware in the C7-623/P. ProTool/Lite is the free configuration tool delivered with the device; the full ProTool is required for recipes and certain alarm-log options.
• ProSave (installed with ProTool) for a non-ProTool backup of the OP image.
• Optional: SIMATIC Automation License Manager if the STEP 7 installation uses license keys.

2.2 Hardware

• PC/MPI adapter (Siemens 6ES7 972-0CA23-0XA0) or USB/MPI adapter (6ES7 972-0CB20-0XA0) with the matching driver installed.
• PROFIBUS MPI cable terminated correctly. Default MPI bus parameters on the C7-623/P are 187.5 kbit/s.
• A free USB or serial port on the programming PC.

2.3 Configuration on the PC

• In Set PG/PC Interface (Windows Control Panel → SIMATIC → Set PG/PC Interface), select PC Adapter (MPI) as the access point of the application.
• Confirm the transmission rate is set to 187.5 kbit/s and that the MPI address of the adapter is set to 0 (the PG default). The C7-623/P typically uses MPI address 2 for the CPU; do not assign this to the adapter.
• Disable any active firewalls that block the ISO/OSI transport used by STEP 7 on local loopback; STEP 7 does not require network access, but Windows Defender firewall rules sometimes intercept the S7DOS services.

3. STEP 7 Upload Procedure

The recommended upload path is the Accessible Nodes (German: Erreichbare Teilnehmer) function in SIMATIC Manager. This function does not require an existing offline project on the PG and works against a C7-623/P that has an unknown or missing project configuration. The source workflow is summarized in the official Siemens manual section covering the online functions of SIMATIC Manager.

3.1 Open the Accessible Nodes View

1. Launch SIMATIC Manager (the STEP 7 V5.x main application).
2. Close any open project that loads automatically.
3. Click the Accessible Nodes button on the toolbar, or select PLC → Display Accessible Nodes from the menu bar.

SIMATIC Manager performs a broadcast over the MPI bus and lists every node that responds, including the C7-623/P and any other devices on the bus (drives, HMI panels on separate addresses, ET 200 stations).

3.2 Identify the C7-623/P CPU

1. In the Accessible Nodes window, expand the MPI subnet.
2. Locate the entry whose address matches the CPU (default 2) and whose object name begins with C7-623. The Online view shows the device type, the rack/slot, and the diagnostic buffer summary.
3. Right-click the entry and select Object Properties to confirm the order number (MLFB) and the firmware version reported by the CPU.

3.3 Upload Station to PG

1. Right-click the C7-623/P entry in the Accessible Nodes window.
2. Select PLC → Upload Station to PG (German: Station in PG hochladen).
3. In the dialog, choose a destination directory and project name. Use an empty directory; do not select an existing project that already contains a S7 program of the same name.
4. Click OK. STEP 7 reads the system data blocks (SDB), the user program blocks, and the CPU configuration from the device and creates a new offline project containing the complete S7 program.

After the upload completes, the new project appears in SIMATIC Manager. Open S7 Program → Blocks to confirm that OB1, the user FC/FB/DB blocks, and the System Data container are populated. The presence of System Data (SDB) is the indicator that the hardware configuration was also retrieved; without SDB the project cannot be re-downloaded as-is.

3.4 Alternative: Copy Blocks to an Existing Project

If an offline project already exists, blocks can be copied individually from the online view to the offline view:

1. In the Accessible Nodes window, open the online Blocks container of the C7-623/P.
2. Open the offline Blocks container of the target project in a second SIMATIC Manager window.
3. Select the online blocks (Ctrl+A for all, or Ctrl+click for a subset), drag-and-drop to the offline container, or right-click and choose Copy then Paste.

This method copies only the block bodies; the SDB must be exported separately with PLC → Upload Station to PG or imported from an archive if the hardware layout is to be preserved.

4. HMI (Operator Panel) Upload with ProTool

The C7-623/P operator panel is configured as a separate ProTool project. The PLC program and the HMI project are independent artifacts in STEP 7, even though they share the same physical device.

4.1 Connect ProTool to the Panel

1. Launch ProTool/Lite (or full ProTool, depending on the project complexity).
2. From the menu, choose File → Download → Project from Device (or Upload, depending on the localized ProTool version).
3. Set the connection type to MPI, the baud rate to 187.5 kbit/s, and the panel address (default 1, distinct from the CPU address 2).
4. Click OK. ProTool reads the HMI project from the panel and writes it to a new .pdb/.ldf file on the PG.

4.2 ProSave Backup (Optional but Recommended)

1. Launch ProSave (installed alongside ProTool).
2. Select the device type matching the C7-623/P OP and the MPI connection.
3. Choose Backup (read from device to file). This produces a compressed backup image that includes firmware, project, and recipes.
4. Store the backup alongside the STEP 7 project using a consistent naming convention (e.g., C7623_MachineA_PLC.zip and C7623_MachineA_OP.psb).

5. TIA Portal Considerations

The C7-623/P predates the TIA Portal generation. TIA Portal can only be used for upload if both of the following are true:

• The integrated CPU firmware is in the TIA-supported range (this typically excludes the earliest C7-623/P CPUs).
• The TIA Portal version includes the legacy S7-300 device package for that specific MLFB.

On the most common C7-623/P configurations, TIA Portal will display the device under Accessible Nodes as an "unsupported device" or will return an error during Upload station to PG such as 0xE0AB0010 ("The device does not support this function") or 0xE0AB0080 ("Online: No valid firmware"). In that case the only working upload path is the STEP 7 V5.x procedure documented in Section 3.

If TIA Portal does detect the CPU, the upload follows the same conceptual path as the Classic workflow: Online → Accessible Devices → Upload from device. The resulting TIA project can be migrated to a newer TIA version later, but a STEP 7 V5.x project cannot be losslessly reverse-migrated to TIA Portal, so keeping the Classic project is mandatory if the device is to be supported long term.

6. Verification

After each upload, perform the verification steps below before signing the upload off as complete.

6.1 PLC Project Verification

1. In SIMATIC Manager, open the uploaded project and select Blocks.
2. Compare the block list against the online view from Accessible Nodes. The block count, names, and timestamps must match.
3. Open System Data and verify that the hardware configuration contains a C7-623/P entry at slot 2 (CPU) and the OP at the expected slot.
4. Cross-check the Diagnostic Buffer (right-click CPU → Module Information → Diagnostic Buffer) on the device against the timestamp of the upload; the buffer should show the upload event at the time of transfer.
5. Run PLC → Verify Block Consistency to confirm that all referenced blocks were uploaded. Missing FC/FB/DB references are the most common silent failure mode.

6.2 HMI Project Verification

1. Open the uploaded ProTool project.
2. Confirm that all configured screens, text lists, and alarm logs are present.
3. If recipes are used, run File → Compile; missing variables are reported as warnings and indicate an incomplete upload.
4. Compare the file size of the uploaded .pdb against the value reported by the panel's system menu (if accessible) to confirm the entire image was read.

6.3 Round-Trip Test

1. Download the uploaded project to a second C7-623/P of the same MLFB on the bench (if available) and confirm a clean startup. The round-trip test is the only definitive verification that the upload captured all SDB entries (PROFIBUS, MPI, and OP connections).

7. Troubleshooting Matrix

8. Field-Commissioning Notes

• Read the diagnostic buffer first. Before initiating an upload, capture the diagnostic buffer to a text file (Module Information → Diagnostic Buffer → Save). If the upload corrupts the project, the buffer provides the only reliable record of the original configuration.
• Note the CPU operating mode. Some C7-623/P firmware versions refuse Upload Station to PG while in RUN. Place the CPU in STOP with the mode selector on the underside of the unit, or via the panel's service menu if the selector is inaccessible.
• Document the OP firmware version. The OP firmware is separate from the CPU firmware. Both are required to recreate the device's runtime. Record both numbers from the panel's system information screen.
• Save the SDB password separately. If the project is SDB-protected, the upload returns an empty System Data container. The password is required to decompile the SDB and reconstruct the hardware configuration; store it in a password manager with a link to the project archive.
• Avoid mid-day uploads on running machines. The upload requires the CPU to be in STOP on many C7-623/P firmware versions. Plan the upload during scheduled downtime to avoid unintentional process interruption.

9. Reference

Refer to the official Siemens documentation for hardware, firmware, and tool-version specifics:

• SIMATIC C7-623, C7-624 Control Systems, Volume 2 — the primary hardware and commissioning manual for the C7-623 and C7-624 compact control systems.

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