SINUMERIK 810D CCU1 Configuration Recovery After Repair

1. Problem Scope and Affected Hardware

• HMI panel (e.g., OP032S) stuck on a "connecting to partner(s)..." status with an incrementing seconds counter.
• No CF card or external backup of the project, NCK machine data, or PLC user program.
• All four status LEDs on the CCU1 flashing or continuously lit.
• 7-segment display of the NC module stuck on a single digit (commonly "6"), indicating that the NCK boot is incomplete.

The hardware generation is no longer in active production. Documentation is consolidated in the SINUMERIK 840D/810D documentation archive under the "SINUMERIK SIMODRIVE 04.2010" CD set, which remains the authoritative source for the CCU1 NCK/PLC start-up switch semantics.

2. Required Tools, Software, and Cabling

Recovery requires the following baseline items:

1. WINPCIN for the PC side (Siemens HMI tool for ASCII/data file transfer). The installer is delivered with SINUMERIK documentation CDs, or it can be re-issued by the original machine builder.
2. A valid NCK series start-up file and a PLC project archive (.dpb / .s7) that exactly matches the machine. These must be sourced from the original machine builder (OBM), the customer's commissioning archive, or a verified backup on the integrator's laptop.
3. An RS232 (V.24) null-modem cable terminated DB9 female on both ends, or the Siemens 6FX2003-0 series cable if the HMI is equipped with the legacy 25-pin connector.
4. A PG/PC with SIMATIC STEP 7 (for PLC diagnostics if a PG/PC is to be connected to MPI).
5. A PG/PC MPI cable (6ES7 972-0CA23-0XA0 or equivalent) for STEP 7 access to the PLC for diagnostics, status, and - if needed - re-flash of the PLC user program.

3. CCU1 Front Panel - LED and 7-Segment Reference

The CCU1 has two distinct LED banks (NC and PLC) and a 7-segment display on the NC side. Use the table below for first-line diagnostics.

The 7-segment display on the NC module provides high-level boot state. The most important codes for this recovery scenario are:

4. CCU1 Start-Up Switches S3 (NC) and S4 (PLC)

Two rotary switches on the front of the CCU1 control the boot behavior of the integrated NCK and PLC runtimes. The switch positions are NOT user-serviceable controls; they are commissioning aids that must be returned to 0 after the procedure is complete.

5. NCK General Reset Procedure

1. Power down the controller completely (24 V OFF, mains OFF).
2. Locate switch S3 on the front of the CCU1. Rotate it to position 1 (NCK general reset).
3. Restore mains power and turn the controller on.
4. Observe the 7-segment display and LED bank. The 0.5V LED must light within a few seconds; the NC LEDs will cycle as the boot phases run.
5. The SRAM is erased during the first successful power-on with S3=1. The next boot will use default machine data.
6. Power down again, return S3 to position 0, and power back up.

The NCK is now in a defined initial state and will be waiting for a partner (PLC and HMI) to be present on MPI/PROFIBUS. The 7-segment display will normally settle on "6" if the PLC is not yet responding correctly.

6. PLC General Reset Procedure

Two options exist for the PLC side. Choose the method that matches the equipment you have on site.

6.1 Method A - Switch S4 on the CCU1

1. Power down the controller.
2. Set switch S4 to position 3 (MRES).
3. Power on. The PLC executes a complete memory reset. The PR/PS/PF/PFO LEDs cycle during the procedure.
4. Wait until the 7-segment display on the NC side shows "6" (NCK waiting for PLC partner). The PLC is now in stop with no user program.
5. Power down, return S4 to position 0 (RUN PROGRAMMING), and power on.

6.2 Method B - STEP 7 Programming Device

1. Connect a PG with SIMATIC STEP 7 to the MPI port of the CCU1 using a 6ES7 972-0CA23-0XA0 cable.
2. Establish an online connection to the PLC. The PLC should report STOP with a cause of "no user program".
3. In the STEP 7 PLC menu, select PLC > Clear/Reset and confirm. The diagnostic buffer is preserved; the program memory is cleared.
4. Download the correct PLC user program from STEP 7.

7. WINPCIN File Transfer Path

WINPCIN is the standard tool for ASCII/data file transfer between a PC and a SINUMERIK HMI. On the 810D/PCU20/MMC100.2 architecture, the file transfer path is:

Key points:

• The CCU1 itself does not expose an RS232 port. All serial file transfers route through the OP/PCU.
• The 9-pin (or 25-pin) D-sub on the rear of the OP032S is the physical WINPCIN endpoint.
• The MPI bus must be intact between OP, PCU, and CCU1; otherwise the HMI cannot reach the NCK to deposit files.
• If the HMI also has no project and is stuck on "connecting to partner(s)...", you cannot reach the Services menu from the HMI key sequence. In that case the HMI must first be re-imaged (MMC100.2 image restore via the PCU20's own recovery path) before the WINPCIN transfer becomes useful.

7.1 WINPCIN Default Parameters

8. HMI/PCU Image Recovery (Pre-Requisite for WINPCIN)

If the OP/PCU also lost its project (no ShopMill RT image, no CF card), WINPCIN alone cannot deliver files to the NCK because the HMI has nothing to broker the transfer. Recovery order must be:

1. Restore the PCU20/MMC100.2 image using a known-good PC card or a parallel-port ghosting procedure. This is OEM-specific; the original machine builder must provide the image.
2. Boot the HMI to a state where the Services menu is reachable via the OP front keys.
3. Establish RS232 from PC to the OP, launch WINPCIN, set the protocol parameters above.
4. On the HMI, navigate to Services > RS-232-C interface and select Read in (binary) or Read in text depending on whether the file is an NCK binary or a text-format PLC archive.
5. On the PC, send the file from WINPCIN. The HMI prompts for a name - use the OEM-specified NCK file name (commonly N_CST_DIR/N_MPF_DIR/INITIAL.INI or similar).

9. File Transfer Failure at 2048 Bytes

The most distinctive file-transfer failure reported on legacy 810D/PCU20 systems is a transfer that completes 2048 bytes of payload and then hangs or aborts. The root cause is truncated or header-damaged source files:

10. Verification Sequence After Recovery

Once WINPCIN transfer completes, perform the following verification steps in order:

1. 7-segment display progresses from "6" through the boot phases and settles on "0" (NCK ready, waiting for partner) or "b" (NCK ready, command output inhibited due to missing enables).
2. HMI no longer shows "connecting to partner(s)..."; ShopMill start-up screen appears.
3. Reference point approach on every axis using the standard procedure (INC/REF, JOG, ref-point key).
4. Confirm PLC RUN LED (PR) is steady green; PS and PF are off.
5. From STEP 7 (if connected), read the PLC diagnostic buffer - it should be empty of operator-actionable faults.
6. Run a controlled spindle test at 0 rpm with command enable, then step to 100 rpm and observe the spindle actual-value on the HMI.
7. Execute a single ShopMill program (dry-run with the safety door open and the dry-run switch engaged) and verify tool-path display on the HMI.

11. Field-Recoverable Failures vs. Hardware Returns

12. CCU1 Battery Management and Long-Term Backup

The CCU1 uses a lithium backup cell to retain SRAM across mains loss. A typical cell is rated for 5-7 years at 25 deg C. Once the cell drops below ~2.7 V loaded, the SRAM is no longer retained.

Best practice after any repair:

1. Measure the battery voltage under load (10 kOhm, 5 s). A healthy cell reads 3.0-3.3 V.
2. Replace the cell if the open-circuit voltage is below 3.0 V or the loaded voltage falls below 2.7 V.
3. After every successful NCK/PLC reload, generate a fresh commissioning archive from the running system. Use the HMI Services > Create archive function, or use STEP 7 PLC > Upload station to PG for the PLC side.
4. Store the archive on at least two independent media (PG HDD and CF card, or PG HDD and a network share).

13. Document References

The following official Siemens documentation is the authoritative source for the procedures above:

• SINUMERIK 840D/810D Descriptions of Functions ShopMill (FBSP) - 12.01 Edition - the FBSP describes ShopMill-specific machine data and HMI behavior.
• SINUMERIK SIMODRIVE documentation set, 04.2010 release - contains the CCU1 commissioning manual, including the S3/S4 switch tables and the NCK/PLC general reset procedures.
• SIMATIC STEP 7 - PLC general reset and download procedure - the canonical reference for the PLC-side MRES semantics on the integrated PLC of the CCU1.

14. Summary - Decision Tree for First Visit

When arriving on site, follow this order of operations:

1. Photograph the LED bank and the 7-segment display.
2. Read the battery voltage under load. Replace if weak.
3. Power down. Set S4=3, power on, observe PLC LEDs. Set S4=0, power on again.
4. If the PLC runs (PR steady green, no PF), connect STEP 7 over MPI and read the diagnostic buffer.
5. Set S3=1, power on, observe NCK boot. Set S3=0, power on again.
6. Confirm the HMI is alive; if not, restore the PCU20 image from OEM backup first.
7. Once the HMI reaches the ShopMill screen, use WINPCIN to transfer the NCK binary, then use STEP 7 or WINPCIN to transfer the PLC archive.
8. Verify reference-point approach and dry-run a ShopMill program.
9. Generate and store a fresh commissioning archive.

If any of steps 3, 4, or 5 produce a steady "all-LEDs-flashing" or "0.5V off" state, the CCU1 module is faulty and must be returned to the repair depot for re-validation. The original repair did not pass final test.