Updating Siemens CP 5711: Resolving Error 0313 and Cyclic Red LED Bus Disruption

The Siemens SIMATIC NET CP 5711 is a USB v2.0 communication processor that connects a programming device (PG) or notebook to PROFIBUS DP or MPI networks. It replaces the legacy CP 5512 (PCI) and CP 5511 (PC Card) adapters and is the de facto standard interface for STEP 7, STEP 5, WinCC flexible, and TIA Portal field service work. When the device enters a fault state with error code 0313 during bus diagnostics or shows a cyclic red LED pattern of three fast flashes followed by a pause, the root cause is almost always a corrupted or outdated boot loader combined with a mismatched SIMATIC NET PC software version.

This guide consolidates the official Siemens procedure for updating the CP 5711 boot loader (Support Entry ID 49973488), the SIMATIC NET PC software installation sequence, the LED/buzzer diagnostic table, and a field-tested troubleshooting matrix that resolves the most common CP 5711 fault signatures.

1. CP 5711 Hardware Identification

Before attempting any update, confirm the exact order number (MLFB) of the device. Only the variant listed below is supported by the boot loader update procedure in Siemens Support Entry 49973488.

The full hardware installation manual is available as PDF: CP 5711 - Operating Instructions (BA_CP-5711_76.pdf).

2. LED and Buzzer Diagnostic Pattern Table

The CP 5711 has a single tri-color LED on the housing that provides bus and device status. The most reported field fault is a red LED that flashes three times rapidly, then pauses, then repeats the cycle — sometimes accompanied by a short beep from the internal buzzer on Windows enumeration. This pattern must be interpreted in combination with the SIMATIC NET diagnostics tool (Configuration Console) output, not in isolation.

3. Error Code 0313 - Root Cause Analysis

Error 0313 in the SIMATIC NET / STEP 7 diagnostic dialog is a bus test failure code raised when the Configuration Console "Test" button is pressed against a CP 5711 that cannot establish a healthy token-passing session. The message window typically returns one of these supplementary strings:

• Internal error in the test routine (0313)
• Test aborted - bus error 0313
• 0313: Firmware / driver mismatch detected

The 0313 code is generated by the SIMATIC NET diagnostic service when one of the following root conditions is true:

1. Boot loader version is older than the firmware build expected by the installed SIMATIC NET version. When a new SIMATIC NET DVD is installed, the firmware inside the CP 5711 is overwritten only if the boot loader supports the new image format. An old boot loader silently rejects the firmware and rolls back — but the diagnostic service interprets the rollback as a 0313 test failure.
2. The CP 5711 is in a partially flashed state following a previous interrupted update (power loss, USB suspend, or wrong driver). The Configuration Console detects the CRC mismatch and reports 0313.
3. USB selective suspend is enabled in Windows power management. The CP 5711 drops off the bus mid-test, and the diagnostic loop times out with 0313.
4. The CP 5512 (PCI) adapter is still installed in the same PG. Two active PROFIBUS interfaces sharing the same PG/PC interface assignment conflict during the test routine and the CP 5711 is starved of bus time.

The 0313 code is therefore a symptom, not a cause. The fix sequence in Section 5 addresses all four root conditions.

4. Boot Loader vs. Firmware - File Size Clarification

Engineers frequently confuse the 135 KB boot loader image distributed through Siemens Support Entry 49973488 with the 2 MB operational firmware. The two are separate deliverables:

Always run the boot loader update first, then reinstall or repair the SIMATIC NET PC software so that a fresh, version-matched firmware image is pushed to the CP 5711.

5. Updating the CP 5711 Boot Loader - Official Procedure

The procedure below is the official Siemens method documented in Support Entry 49973488. Execute every step in order. The procedure does not require STEP 7 to be running, but it does require administrator rights on the PG/PC.

5.1 Prerequisites

• PG/PC with Windows 7 SP1, Windows 10 (1809 or newer recommended), or Windows 11 (with driver-signing override for older SIMATIC NET builds).
• Local administrator account.
• The CP 5711 physically disconnected from the PG/PC USB port during the download of the update package.
• A working SIMATIC NET PC Software V8.0 SP2 or higher installation (V8.2 recommended). Without SIMATIC NET installed, the CP 5711 is not enumerated by Windows and the loader cannot find the device.
• Free USB 2.0 port directly on the PC, not behind an unpowered hub.

5.2 Pre-Update: Remove Legacy Hardware Conflicts

1. Shut down the PG/PC.
2. Open the chassis and physically remove the CP 5512 PCI card if present. Leaving it in the system creates an address conflict that the boot loader cannot resolve.
3. Close the chassis and restart.
4. Open Device Manager → Network Adapters and confirm that no entry named SIMATIC NET CP 5512 or CP 5611 remains visible.
5. If entries are visible with a yellow exclamation, right-click → Uninstall device → check Delete the driver software for this device.

5.3 Download the Boot Loader Update

1. Navigate to https://support.industry.siemens.com/cs/document/49973488.
2. Sign in with a Siemens Industry Online Support account (free registration).
3. Download the ZIP archive named CP5711_BootLoader_Update_Vx_x.zip (version visible in the entry header).
4. Verify the SHA-1 checksum published on the support entry against the downloaded file.
5. Extract the archive to a local path, e.g. C:\Siemens\CP5711_BootLoader.

5.4 Execute the Boot Loader Update

1. Confirm SIMATIC NET PC Software is installed. If not, install it first (Section 6).
2. Connect the CP 5711 to a USB 2.0 port. Wait for Windows to enumerate the device (Device Manager should show a new entry under Network Adapters or Universal Serial Bus controllers).
3. Open SIMATIC NET Configuration Console from the Start menu (Siemens Automation → SIMATIC NET → Configuration Console).
4. Confirm that the CP 5711 is visible as CP 5711 under Modules. If it is not visible, the driver did not load — re-install SIMATIC NET.
5. Close the Configuration Console (it must not be running during the flash).
6. Open an elevated command prompt (Run as administrator) and cd into the extracted folder.
7. Run the loader executable:

   CP5711_BootLoader_Update.exe -update -force

8. The tool detects the CP 5711, erases the boot loader flash sector, and writes the new image. Progress is shown as a percentage. The red LED on the CP 5711 will switch off and then briefly flash yellow during the verify phase.
9. When the tool reports Update successful — please reconnect the device, unplug the USB cable, wait 5 seconds, and reconnect.

5.5 Post-Update Verification

1. Open the Configuration Console. The CP 5711 should now show a new Firmware version in the properties pane.
2. Open Set PG/PC Interface (from STEP 7 or the SIMATIC NET folder). Select CP 5711 (PROFIBUS) as the access point of the application.
3. Click Diagnostics → Test. The test should now complete without raising 0313.
4. If the test still fails, proceed to Section 8 — the boot loader update alone is not sufficient; the SIMATIC NET PC software may also require a repair install.

6. SIMATIC NET PC Software Installation

If the boot loader update completes but the CP 5711 still does not enumerate correctly, the SIMATIC NET PC software must be (re)installed so that the operational firmware (the ~2 MB image) is pushed to the device. The installation order is critical.

1. Uninstall any existing SIMATIC NET PC Software from Control Panel → Programs and Features. Restart.
2. Insert the SIMATIC NET DVD or mount the ISO. Launch Setup.exe as administrator.
3. Choose Custom Installation and enable at minimum:
   • SIMATIC NET PC Software core
   • CP 5711 driver module
   • OPC server (optional, required only for OPC bridging)
4. During installation, do not connect the CP 5711. The installer must register the unsigned/signed driver catalog before any device is plugged in.
5. Complete the installation and restart.
6. After restart, connect the CP 5711. Windows will enumerate it as Siemens CP 5711.
7. The Configuration Console will detect the device and automatically push the bundled firmware image. This second-stage push takes 30–60 seconds; the LED will switch to green solid when complete.

7. Driver Configuration and PG/PC Interface Assignment

Even with a healthy CP 5711, the wrong access point of the application causes STEP 7 and WinCC flexible to silently fall back to the TCP/IP access path and never touch the PROFIBUS interface. The correct assignment is:

1. Open Start → Siemens Automation → SIMATIC → Set PG/PC Interface.
2. In the Access Point of the Application dropdown, select S7ONLINE (STEP 7) -> CP 5711 (PROFIBUS).
3. Click Properties → confirm the PROFIBUS address (default 0, but the PG can also be set to addresses 1–126) and the transmission rate (default Autodetect, fixed 1.5 Mbps is recommended for noisy environments).
4. Click Diagnostics. The dialog should return OK and a list of active stations on the bus with their diagnostic addresses.
5. If the diagnostic list is empty, the bus is physically OK but no master/slave is responding — check that the PLC is in RUN or RUN-P and that the PROFIBUS connector is in the correct OUT position with termination ON at the end nodes only.

8. Troubleshooting Matrix

The matrix below maps the most common reported field symptoms to the validated corrective action. Use it in conjunction with the Configuration Console diagnostic log.

9. Field-Proven Edge Cases and Caveats

9.1 Coexistence with CP 5611 / CP 5613 / CP 5621

The CP 5711 is the USB sibling of the PCI Express cards CP 5611, CP 5613, and CP 5621. If more than one PROFIBUS interface is installed, the SIMATIC NET Configuration Console assigns module indices automatically. Verify in the console that only one interface is bound to the S7ONLINE access point. Duplicate bindings cause the diagnostic test to fail with 0313 even when every individual interface is healthy.

9.2 Using CP 5711 on 64-bit Windows 11

Windows 11 22H2 and newer enforce HVCI (Hypervisor-protected Code Integrity) by default, which blocks legacy unsigned drivers. SIMATIC NET V8.2 SP1 is the first release to provide a fully signed driver that loads under HVCI. If you must use an older SIMATIC NET, add the boot-start Early Launch Anti-Malware (ELAM) exemption for the CP 5711 driver via bcdedit /set nointegritychecks on — and reverse this setting before returning the PG to production use.

9.3 USB 3.0 Port Interoperability

The CP 5711 is USB 2.0 only. While it will physically fit a USB 3.0 (blue) port, some host controllers on Intel 8-series and AMD 500-series chipsets exhibit enumeration timeouts when a USB 2.0 full-speed device negotiates with a USB 3.0 hub. If the LED never lights, switch to a native USB 2.0 port (typically black on the chassis).

9.4 Long Cable Runs and Ground Loops

The 2 m USB cable included in the CP 5711 packaging is shielded. On industrial floors, ground potential differences between the PG chassis and the PLC rack can drive several mA through the USB shield, corrupting PROFIBUS DP telegrams. Symptoms appear as 0313 errors only when the bus is connected. Insert a USB isolator (e.g. B&B IL-USB-1 or equivalent) between the PG and the CP 5711 when the PG is powered from a different source than the PLC.

9.5 Boot Loader Update Fails Mid-Flash

If the USB cable is disconnected or the PG enters sleep during the flash, the boot loader is left in an inconsistent state. The CP 5711 will enumerate with a Yellow solid + Red single flash pattern. Reconnect the device; the loader image is idempotent and Siemens' update tool detects the partial state and re-flashes automatically on the next run. No hardware-level recovery is required.

10. Related Standards and Compliance

The CP 5711 is certified against the following standards; refer to the declarations in the operating instructions PDF (BA_CP-5711_76.pdf) for the current DoCs.

• EN 50170-2 / IEC 61158 (PROFIBUS DP, MPI physical layer)
• EN 61000-6-2 / EN 61000-6-4 (industrial EMC immunity/emission)
• EN 61131-2 (programmable controller environmental)
• USB 2.0 Specification (full-speed, 12 Mbps)
• RoHS 2011/65/EU, REACH (EC 1907/2006)
• UL 508 / cULus listed for industrial control equipment

These standards define the bus timing budgets and EMC limits within which the CP 5711 is warranted to operate. The 0313 error is not a bus-timing violation — it is a software/firmware-state machine error, which is why the boot loader update resolves it where a bus-analyzer cannot.

11. Spare Parts and Replacement Strategy

If the CP 5711 remains in the red-flash state after two consecutive boot loader updates and a clean SIMATIC NET reinstall, the flash memory is end-of-life (typical NAND endurance is 100 k cycles, and industrial users performing many firmware revisions can exhaust it). Order a replacement as:

• MLFB: 6GK1571-1AA00 (current production)
• Alternative refurbishment: Return-to-Siemens via the SIMATIC NET RMA process (Spare Part Service). Do not attempt to desolder the NAND — the device is not field-serviceable at the component level.

Keep one spare CP 5711 in the service kit; the boot loader and SIMATIC NET are portable between units, so a swap takes less than 5 minutes including driver recognition.

12. Quick Reference Procedure (T-Shirt Card)

Print the following condensed procedure and keep it with the service PG:

CP 5711 ERROR 0313 - QUICK FIX
==============================
1. Disconnect CP 5711 from USB.
2. Remove any CP 5512 PCI card from PG.
3. Download boot loader from:
   https://support.industry.siemens.com/cs/document/49973488
4. Extract to C:\Siemens\CP5711.
5. (Re)install SIMATIC NET PC Software V8.2 SP1+.
6. Restart PG.
7. Connect CP 5711 to USB 2.0 port (black).
8. Open Configuration Console > verify CP 5711 visible.
9. Close Configuration Console.
10. Open elevated CMD, run:
    CP5711_BootLoader_Update.exe -update -force
11. Reconnect USB when prompted.
12. Set PG/PC Interface > S7ONLINE > CP 5711 (PROFIBUS).
13. Diagnostics > Test > expect OK.