Resolving WinAC RTX CP5613 Profibus Communication Failure

Problem Overview

WinAC RTX (Windows Automation Center with Real-Time eXtension) installations based on the CP5613 A2 PCI Profibus master card can lose DP-bus communication after a controlled shutdown, a power loss, or an OS image deployment. The PC boots, the RTX subsystem starts, the user program loads, but the 8 (or more) DP slaves report no cyclic I/O, and the CP5613 disappears from the configuration console. Driver reinstallation alone often does not resolve the issue unless it is paired with a Station Configurator re-bind, an Enhanced Write Filter (EWF) commit, and a fresh HW Config download.

This reference documents the field-proven recovery procedure for a CP5613 A2 attached to a WinAC RTX / WinLC v4.x controller, including the EWF-related root cause, the driver reset sequence, and the secondary WinLC v4.6 HMI freeze issue that often follows a botched CP restart.

WinAC RTX System Architecture

WinAC RTX is a PC-based soft-PLC from Siemens that pairs a Windows user space with the Ardence (later IntervalZero) RTX real-time subsystem. Communication with the Profibus DP network is delegated to a Siemens CP5613 A2 (PCI) or CP5614 A2 (PCIe) Profibus master card. The relevant software stack on a typical installation:

Because the CP5613 is registered both to the Windows DP master and to the RTX-side WinLC, the configuration must be consistent on both sides. The Station Configurator Editor and the SIMATIC NET Commissioning tool are the only sanctioned way to bind the CP to a PC station index used by WinLC RTX.

CP5613 A2 Hardware Configuration

Before any driver-level recovery, verify the physical layer and PCI enumeration:

1. Open Device Manager and confirm the CP5613 A2 appears under SIMATIC NET with no yellow exclamation mark.
2. Check the PCI slot: avoid shared IRQ lines. The CP5613 should be in a slot that does not share IRQ with USB controllers or SATA ports.
3. Verify Profibus segment termination. The first and last node must have termination ON; all intermediate nodes OFF.
4. Measure the bus voltage between pin 3 (Data+) and pin 8 (Data-): a healthy segment reads approximately 1.0 V DC differential when terminated, with a 5 V idle bias between pin 6 (VP) and pin 5 (GND).
5. With the DP connector disconnected from the CP, open Configuration Console (Start > SIMATIC > SIMATIC NET > Configuration Console). The CP5613 should still appear under Modules. If it does not, the driver layer is corrupt and must be reset before any further diagnosis.

Symptom Matrix: Profibus Failure Modes

Root Cause Analysis

The dominant root cause for a CP5613 that vanishes from the Configuration Console after a Windows shutdown is registry-level driver corruption. The CP5613 driver stores a per-instance configuration under HKLM\SOFTWARE\Siemens\SIMATIC_NET\CP5613 including the assigned Profibus address, the bus parameters (Tslot, Tset, Ttr, min Tsm), and the RTX-side handshake token. When Windows is killed by power loss or by a hard reset during a config write, this key is left in an inconsistent state. Subsequent driver startup fails silently, the device manager entry becomes a phantom, and Configuration Console no longer enumerates the module.

Secondary causes that must be ruled out:

• Enhanced Write Filter (EWF) enabled: changes to SIMATIC NET configuration files under %ProgramFiles%\Siemens\SIMATIC_NET are written to a RAM overlay and discarded on the next boot. The station appears to forget its CP5613 binding on every restart.
• User Account Control (UAC) on Windows 7 embedded: the Station Configurator Editor must be launched elevated to commit changes. Without elevation, the binding appears to succeed but is silently rejected.
• PCI power management (Windows default): the CP5613 can be put in D3 sleep state, which RTX does not wake correctly. Disable PCI power management in Device Manager > CP5613 > Power Management.

Pre-Recovery Diagnostic Checklist

1. Open Configuration Console. Record the bus parameters of the CP5613 (Profibus address, baud rate, profile).
2. Open Station Configurator Editor (Start > SIMATIC > Station Configurator Editor). Record the current Index assigned to the CP5613 and the PC station name.
3. Open STEP 7 HW Config. Note the PC station number, CP5613 order number (6GK1561-3AA01), and the slot assignment.
4. Determine EWF state: open a command prompt, run ewfmgr c:. If the volume is RAM (RAMP) and overlay data exists, you must either commit the overlay or disable EWF before making any change.
5. Open the WinLC RTX diagnostic viewer. Save the last 200 lines of the diagnostic log to a file for comparison after recovery.

Step-by-Step Recovery Procedure

The following procedure has been validated on WinAC RTX 2010, WinAC RTX 2008, and WinLC v4.6 against CP5613 A2 firmware 5.2.x and earlier. Adapt the SIMATIC NET version path to the installed release.

Step 1 - Disable EWF (Embedded Systems Only)

On XP Embedded, WES 2009, or WES 7 systems, disable the Enhanced Write Filter to prevent loss of committed configuration on the next boot:

ewfmgr c: -disable

Commit any pending overlay with ewfmgr c: -commit only if you intend to preserve prior changes. After the recovery is complete, re-enable EWF and re-commit the working configuration:

ewfmgr c: -enable

Step 2 - Uninstall the CP5613 Driver

1. Open Control Panel > SIMATIC NET > Commissioning and stop the SIMATIC NET service.
2. Open Device Manager, right-click CP5613, select Uninstall. Check Delete the driver software for this device.
3. Alternatively, run the SIMATIC NET Setup in maintenance mode (%ProgramFiles%\Siemens\SIMATIC_NET\setup.exe) and remove the CP5613 component only.
4. Reboot the PC. The CP5613 should now appear in Device Manager as an unknown PCI device with hardware ID PCI\VEN_10B5&DEV_9050.

Step 3 - Reinstall the CP5613 Driver

1. Run the SIMATIC NET setup. Re-select the CP5613 driver component.
2. During setup, assign the PC station index matching the index used in HW Config (typically index 0 or 1).
3. Set the CP5613's Profibus address to the value expected by the DP slaves (commonly 1, the default master address).
4. Apply the same bus profile that was recorded in Step 1 of the diagnostic checklist.

Step 4 - Re-bind in Station Configurator Editor

1. Launch Station Configurator Editor elevated (right-click > Run as administrator).
2. Select the PC station node, click Import Station, and load the matching .XDB file exported from HW Config.
3. Confirm that the CP5613 is shown with the correct slot and order number (6GK1561-3AA01 for CP5613 A2).
4. Click Apply. The editor writes the new binding to %ProgramFiles%\Siemens\SIMATIC_NET\opc2\bin\S7oiehsx.ini and the registry.

Step 5 - Download the Hardware Configuration

1. Open STEP 7 and connect to the target PC station via TCP/IP (default port 102).
2. Open HW Config, verify the PC station matches the local configuration, and click Download to Target.
3. Confirm the prompt to overwrite the PC station. The HW Config download triggers a restart of the SIMATIC NET services and a re-bind of the CP.

Step 6 - Download Program Blocks

1. In STEP 7, switch to the program editor view and select Download > All Blocks.
2. WinLC RTX will start in RUN if the OB 1, OB 100, and the DP error OBs (OB 82, OB 86, OB 122) are present and consistent.
3. Open the online diagnostic buffer of the WinLC. Confirm that the CP5613 transitions from DP slave failure to DP slave OK for each configured slave.

Enhanced Write Filter (EWF) Configuration

Embedded installations of WinAC RTX almost always run with EWF enabled to protect the OS partition from corruption. The CP5613 driver and Station Configurator changes are written under %ProgramFiles%\Siemens and %ProgramData%\Siemens, both of which are subject to the EWF overlay.

WinLC v4.6 Screen Freeze: Secondary Issue

After the CP5613 is restored, operators may report a secondary symptom: the WinLC v4.6 status display or the HMI screen remains frozen on the last drawn frame, although the Profibus traffic and the diagnostic LEDs are healthy. This is a separate fault class and is caused by one of three conditions.

Cause 1 - WinLC Service Halted

WinLC v4.6 runs as a service (WinLCRT) under the Local System account. If the Local System account lacks the SeInteractiveLogonRight privilege (default on hardened XP Embedded images), the service starts but the OPC server cannot enumerate. Verify the service is Started in services.msc. If it is in Start Pending, grant Local System the Log on locally right in secpol.msc.

Cause 2 - HMI Connection Token Stale

WinCC flexible and older WinCC panels cache the OPC DA 2.0 subscription token. After a CP reset, the token references a dead subscription handle. Restart the HMI runtime, or in the HMI project, set the OPC connection Reconnect time to 5 s and Reconnect count to unlimited.

Cause 3 - RTX Real-Time Clock Drift

If WinLC v4.6 is configured with a software clock on RTX, a Profibus restart can desynchronize the software clock from the hardware RTC. The HMI freezes waiting for a cycle handshake that never completes. Open WinLC Properties > Real-Time Settings and switch the time base from Software Clock to Hardware Clock, then restart WinLC.

Verification and Commissioning

After recovery, perform the following verification sequence before returning the line to production:

1. Open the WinLC online diagnostic buffer. Confirm the most recent entries show DP: All configured slaves are in data exchange with no SF entries.
2. In the Configuration Console, select the CP5613 and click Bus Statistics. Verify zero Bus Errors and zero Repeated Frames over a 60-second observation.
3. Force a single output on each DP slave from STEP 7 in monitor/modify. Confirm the corresponding input changes state on the next cycle.
4. Cycle power to a single DP slave. Confirm OB 86 is triggered, the slave is reported as failed, and OB 86 re-inserts the slave within the configured retry window (default 3).
5. Cycle power to the entire PC. Confirm the system re-acquires all slaves within 30 seconds without operator intervention.
6. If EWF is in use, commit the working configuration: ewfmgr c: -commit.
7. Re-enable EWF if it was disabled for the procedure: ewfmgr c: -enable.

Preventive Measures

• Always perform a controlled Windows shutdown before cutting power to a WinAC RTX PC. Set the BIOS to power back on after AC loss to Last State to avoid surprise boots on unstable power.
• Schedule a daily export of the Station Configurator XDB file to a network share. The export is stored in %ProgramFiles%\Siemens\SIMATIC_NET\opc2\bin and can be re-imported in under 60 seconds.
• Use a UPS rated for at least 10 minutes at full load. WinAC RTX is rated for hard shutdowns but the CP5613 driver corruption rate rises sharply after three uncontrolled shutdowns in a 30-day window.
• Disable Windows automatic updates on the WinAC RTX host. Driver updates from Windows Update can silently replace the CP5613 driver with an unsigned generic PCI bridge driver.
• Pin the CP5613 driver version in the registry: HKLM\SOFTWARE\Siemens\SIMATIC_NET\CP5613\DriverVersion. Compare to a known-good baseline weekly.

Field-Proven Caveats

• The CP5613 A2 and the CP5613 A3 are not drop-in replacements. A2 cards (order number 6GK1561-3AA01) require SIMATIC NET v6.4 or earlier for legacy WinAC RTX. A3 cards (6GK1561-3AA02) require SIMATIC NET v7.1+ and a hotfix for the RTX handshake.
• If WinLC RTX is paired with a CP5623 (PCIe), the Station Configurator binding is a different GUID. Re-importing the XDB of a CP5613 into a CP5623 system will fail silently. Verify the order number in HW Config before re-importing.
• On Windows 10 IoT Enterprise LTSC 2019 and later, RTX 2014 (the last released version) is not WHQL-signed. Disable driver signature enforcement with bcdedit /set nointegritychecks on and reboot. The driver signing policy cannot be relaxed by group policy alone.

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