Siemens CP5711 USB-MPI Adapter Boot Loader Update and Alarm

Siemens CP5711 USB-MPI Adapter: Boot Loader Update and Alarm 120202 Resolution

The Siemens SIMATIC NET CP 5711 (order number 6GK1571-1AA00) is a USB 2.0 communication processor that connects a programming device (PG), notebook, or PC to PROFIBUS DP or MPI networks. It replaces legacy PCMCIA and serial adapters that required an external 24 V DC supply or a parallel port. The CP 5711 derives its operating power directly from the USB port and supplies termination power to the PROFIBUS segment through its integrated bus interface, removing the need for an external power supply in most commissioning scenarios.

This technical reference covers the CP 5711 hardware specifications, STEP 7 / HMI Advanced configuration, the integrated PROFIBUS termination power behavior, the boot loader update that corrects a known termination-power loss condition, and the resolution of alarm 120202 reported by SINUMERIK HMI Advanced when the PG/PC interface is misconfigured. Field-validated commissioning steps are included for SINUMERIK 810D backup/restore and STEP 7 V5.x project download workflows.

Hardware Identification and Order Data

The complete product catalog entry and firmware notes are maintained in the Siemens Industry Online Support portal under the CP 5711 product tree. Reference the Siemens CP 5711 product support page for the latest firmware revisions and manual revisions.

Installation Prerequisites

Before connecting the CP 5711 to a PG/PC, confirm the following prerequisites.

1. Operating system architecture. Use a Windows version that matches the driver CD. 64-bit Windows 7 systems require the 64-bit driver variant from the bundled media. Verify the driver revision in Device Manager > Universal Serial Bus controllers > SIMATIC NET CP 5711 after first plug-in.
2. Administrator privileges. Driver installation requires local administrator rights for the USB device class and for the SIMATIC NET service registration. Close STEP 7, HMI Advanced, and any PG/PC interface dialog before installing.
3. STEP 7 license key. The CP 5711 functions as a passive bus node; STEP 7 V5.x must be licensed on the host. No CP 5711-specific license is required.
4. PROFIBUS connector with termination. Use a Siemens PROFIBUS connector (6GK1500-0FC00 or 6ES7972-0BA12) with switchable termination. The CP 5711's DB-9F connector follows the PROFIBUS EN 50170 pinout (pin 3 RxD/TxD-P, pin 8 RxD/TxD-N).
5. USB port power budget. Use a powered USB port directly on the notebook. USB hubs without external power may fail to enumerate the CP 5711 under PROFIBUS load.

Driver Installation and STEP 7 PG/PC Interface Assignment

Install the driver from the CD supplied with the CP 5711 before first connection. The driver registers the SIMATIC NET CP 5711 as a virtual PROFIBUS adapter visible to the PG/PC interface dialog.

1. Insert the driver CD. Run Setup.exe from the root or from \CP5711\Driver\.
2. Follow the SIMATIC NET installation wizard. Accept the default installation path C:\Program Files\Siemens\Automation\SIMATIC_NET.
3. Restart the PC when prompted.
4. Connect the CP 5711 to a USB 2.0 port. Windows enumerates it as SIMATIC NET CP 5711.
5. Open PG/PC Interface from Start > SIMATIC > STEP 7 > PG/PC Interface.
6. Select CP5711 (PROFIBUS) as the interface assignment. Click Properties and verify the COM-port-free PROFIBUS address (typically 0 for the PG).
7. Click Diagnostics > Test to confirm the PG can read its own PROFIBUS node. The test must report OK with the CP 5711 LED in steady green state.

If the test returns Error 0x031A: Connection to the CP 5711 failed, verify the driver is loaded (Device Manager), that no other application (HMI Advanced, TIA Portal) holds the CP 5711 exclusively, and that the USB root hub has not suspended the device for power saving.

PROFIBUS Termination Power Behavior

PROFIBUS DP segments require termination at both physical ends of the bus to suppress reflections on the RS-485 differential pair. The standard termination is implemented in the PROFIBUS connector as a three-resistor network: 220 Ω between the two data lines, plus 390 Ω pull-up to +5 V and 390 Ω pull-down to ground on each line (per IEC 61158-2 / EN 50170).

The CP 5711 normally sources this +5 V termination power from its internal USB-derived supply and injects it onto the bus when termination is enabled at the connector. Under three specific conditions, however, the integrated boot loader firmware leaves the termination power rail off:

1. Immediately after a fresh CP 5711 driver installation on a previously unused USB port.
2. Immediately after the CP 5711 is unplugged and reinserted (hot-plug cycle) on the same USB port.
3. After a computer restart while the CP 5711 remains plugged in.

In each case, the CP 5711 only enables termination power once a user application opens the bus — for example, when STEP 7 launches, when the PG/PC interface test dialog opens the bus, or when HMI Advanced starts a connection. If no user application opens the bus, the CP 5711 sits as the silent last node on the segment, and any other node further down the line loses termination, producing intermittent communication errors (typically F-code receive errors, retry storms, and the bus LED on slaves flickering red instead of steady green).

Boot Loader Update Procedure

Siemens released an updated CP 5711 boot loader that holds termination power active regardless of whether a user application has opened the bus. The update is field-installable and is documented in Siemens support entry 49973488.

1. Download the boot loader ZIP archive from Siemens support entry 49973488. Verify the file size matches the 134 KB published size and that the SHA matches the value in the Siemens readme.
2. Extract the ZIP to a local folder. Read Liesmich.txt (German) or readme.txt (English) for the exact revision history and minimum CP 5711 firmware baseline required.
3. Close STEP 7, HMI Advanced, TIA Portal, and any application that may hold the CP 5711 exclusive.
4. Run the bundled executable (typically BootLoaderUpdate_CP5711.exe) as administrator.
5. The update tool detects the connected CP 5711, displays the current boot loader version, and prompts for confirmation.
6. Click Update. Do not disconnect the CP 5711 or power off the PC during the flash. The tool reports success in approximately 30–60 seconds.
7. Restart the PC. After restart, verify that the CP 5711 supplies termination power immediately, before any user application opens the bus. Use a multimeter on the PROFIBUS connector's +5 V termination pin (pin 6) referenced to DGND (pin 5) — the reading must be > 4.75 V DC without STEP 7 running.

HMI Advanced Integration and Alarm 120202

HMI Advanced is the PC-based HMI runtime used with SINUMERIK 810D/840D and the legacy ProTool/Pro operator panels. HMI Advanced uses the same PG/PC interface assignment dialog as STEP 7 to acquire the CP 5711 as a PROFIBUS node. When the CP 5711 is selected correctly, HMI Advanced performs the following operations against the connected NCU/PLC:

• Series start-up backup/restore (data archive read/write).
• NCK commissioning access.
• PLC upload/download via the integrated STEP 7 interface.
• Cross-reference and signal diagnostics.

When the PG/PC interface assignment is incorrect — most commonly when HMI Advanced is pointed at CP5611 or Internal instead of CP5711 (PROFIBUS), or when the MPI/PROFIBUS baud rate in the HMI Advanced connection settings does not match the bus — HMI Advanced logs alarm 120202 on startup. The alarm indicates that no live connection could be established to the NCU on the configured PROFIBUS address. HMI Advanced releases 6.3 and 7.5 both surface this alarm on the alarm line of the operator interface.

Resolution procedure:

1. Open Start > SIMATIC > HMI > PG/PC Interface (HMI Advanced uses its own copy of the dialog).
2. Set the interface to CP5711 (PROFIBUS) with the correct transmission rate. For SINUMERIK 810D the default is 1.5 Mbps MPI/DP; confirm against the NCU's bus configuration via Commissioning > Bus Configuration on the HMI.
3. In HMI Advanced, open Services > Connections and verify the target NCU PROFIBUS address (default 0 for the NCU; the CP 5711 must use a different PG address, typically 0 — adjust if address conflict).
4. Restart the HMI Advanced runtime. Alarm 120202 should clear within one connection cycle (approximately 10 seconds).

SINUMERIK 810D Field Application Notes

The CP 5711 is a verified programming adapter for SINUMERIK 810D powerline and 810D solution line NCUs when paired with STEP 7 V5.x and HMI Advanced. Field-validated workflows include:

• Series start-up archive backup. From HMI Advanced, select Services > Series Start-up > Read. The CP 5711 handles the PROFIBUS DP handshake with the NCU's integrated PLC. Typical archive size 8–32 MB; transfer time 30–90 seconds at 1.5 Mbps.
• PLC block download. From STEP 7, select PLC > Download. The CP 5711 supports online block download at 1.5 Mbps MPI without disrupting the NCK's HMI-to-NCK link.
• Cross-reference and signal diagnostics. STEP 7 online view works against the 810D PLC (the integrated S7-300 module on the NCU) without affecting NCK operation.

For 840D sl / SINUMERIK Operate on PC environments released after 2013, the CP 5711 is no longer the recommended path — use the Ethernet-based PG/PC interface with the X130 or X127 NCU port instead. The CP 5711 remains the correct choice for legacy 810D/840D powerline environments where PROFIBUS is the only operator/engineering access.

Comparison: CP 5711 vs. Legacy PROFIBUS Adapters

For new deployments on workstations without legacy slots, the CP 5711 with the post-update boot loader is the recommended Siemens-supplied PROFIBUS/MPI adapter until the move to Ethernet-based SINUMERIK commissioning is complete.

Troubleshooting Matrix

Best Practices for Field Commissioning

• Apply the boot loader update on every CP 5711 before first use. Even brand-new units ship with the older boot loader and will exhibit the termination-power issue until updated.
• Configure STEP 7 and HMI Advanced PG/PC interface separately. The two tools share a dialog but store independent settings. Document the CP 5711 address and baud rate for both.
• Use the latest driver revision. Driver CD revisions vary by shipment date. The Siemens CP 5711 support page lists the current driver as a separate download.
• Avoid USB suspend. Disable Windows USB selective suspend for the CP 5711's USB root hub in Power Options to prevent the device from powering down during long programming sessions.
• Reserve a fixed PG PROFIBUS address. Use address 0 for the PG only when no other node occupies it. Otherwise assign a dedicated free address (e.g. 126) and document it on the panel.
• Verify termination power after every PC restart. Use the multimeter gate described in the boot loader update procedure. This is a 10-second check that prevents hours of slave debugging.

Standards and Reference Documents

• EN 50170 / IEC 61158-2 — PROFIBUS physical layer (RS-485, termination network, bus speed vs. segment length).
• Siemens SIMATIC NET CP 5711 manual — see Siemens CP 5711 product support page.
• Siemens Support Entry 49973488 — CP 5711 boot loader update.
• Siemens Industry Online Support — support.industry.siemens.com.

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