Resolving CP 1623 Code 10 Device Start Failures on HP ProLiant Gen9 Servers in PCS 7

In SIMATIC PCS 7 v8.1 SP1 systems deployed on HP ProLiant DL380/DL360 Gen9 servers running Windows Server 2008 R2 64-bit, the CP 1623 communications processor (6GK1162-3AA00) fails to start with a yellow warning triangle in Device Manager (Error Code 10: 'Device start failed', Event ID 1536) due to an incompatibility in HP BIOS versions v2.00 to v2.22 regarding PCIe 64-bit Memory Mapped I/O (MMIO) allocation. Updating BIOS to v2.22 does not resolve the issue. To fix this, downgrade the HP system BIOS to version v1.40 (P89), or disable 64-bit MMIO above 4GB in HP UEFI PCIe configuration.

Hardware Overview: CP 1623 and Fault-Tolerant S7-410-5H Communication

In high-availability SIMATIC PCS 7 architectures, OS Servers communicate with fault-tolerant S7-400H / CPU 410-5H controllers (6ES7410-5HX08-0AB0) over redundant Industrial Ethernet plant buses.

This fault-tolerant S7 communication requires the CP 1623 communications processor (6GK1162-3AA00):
* Hardware Interface: PCI-Express x1 host interface with onboard ARM communications processor and integrated 2-port Gigabit switch.
* Software Protocol: Operates with SIMATIC NET Hardnet S7-REDCONNECT (6GK1716-0HB...) to provide bumpless switchover between redundant plant bus rings without dropping WinCC process tags.

While commonly installed in Siemens Industrial PCs (IPC647D, IPC847D), enterprise customer standards often dictate deploying commercial rackmount servers such as the HP ProLiant DL380 Gen9.

Root Cause of Code 10 and Event ID 1536 on HP Gen9 Servers

When installing the CP 1623 into an HP ProLiant DL380 Gen9 server running Windows Server 2008 R2 64-bit or Windows Server 2012 R2:
* Windows Device Manager displays a yellow exclamation triangle on SIMATIC NET CP 1623.
* Device Properties reports: This device cannot start. (Code 10).
* Windows System Event Log records errors from source WDM1623, Event ID 1536:
CP1623(1): An internal error occurred. Device start failed.
* Underlying Failure Mechanism: In HP ProLiant Gen9 BIOS/UEFI revisions starting with version v2.00, HP revised the PCI-Express Base Address Register (BAR) memory mapping, aggressively assigning 64-bit MMIO memory resources above the 4 GB physical boundary. The NDIS/WDM kernel driver for CP 1623 (wdm1623.sys) expects legacy 32-bit MMIO address windows below 4 GB, causing the device driver initialization handshake to abort.

HP ProLiant Gen9 BIOS Incompatibility Matrix

The following table details the compatibility observed between HP ProLiant Gen9 server ROM versions and the Siemens CP 1623 communications processor:

HP Server ROM / BIOS VersionRelease DateCP 1623 Operational StatusBehavior in Windows Device ManagerHP BIOS v1.40 (P89)June 2015FULLY OPERATIONALDevice starts cleanly; driver loads without error.HP BIOS v2.00 (P89)Dec 2015INCOMPATIBLECode 10: Device start failed. Event ID 1536.HP BIOS v2.20 / v2.22Mid 2016INCOMPATIBLECode 10: Device start failed. BAR mapping conflict persists.HP BIOS v2.40+ (Patched)2017+Operational (Configured)Requires enabling 'PCIe 32-bit MMIO Legacy Mode' in UEFI.

Table 1: HP ProLiant Gen9 BIOS compatibility with SIMATIC NET CP 1623.

Step-by-Step BIOS Downgrade and Configuration Procedure

To restore proper PCIe memory allocation and bring the CP 1623 online:

Obtain HP BIOS v1.40:
* Download the official HP ProLiant DL380 Gen9 System ROM version P89 v1.40 (05/06/2015) from the HPE support portal.
Flash System ROM via HP iLO:
* Log into the server's HP Integrated Lights-Out (iLO 4) web interface.
* Navigate to Administration > Firmware.
* Upload the P89 v1.40 ROM image file and execute the firmware flash.
* Reboot the server.
Configure UEFI PCI Settings:
* During server POST, press F9 to enter System Utilities.
* Navigate to System Configuration > BIOS/Platform Configuration (RBSU) > PCIe Device Configuration.
* Locate the PCIe slot containing the CP 1623.
* If available, ensure 64-bit Resource Allocation (MMIO above 4GB) is set to Disabled or set to Legacy Mode.
* Save settings and boot into Windows Server.
Driver Re-enumeration:
* In Windows Device Manager, right-click the CP 1623 and select Scan for hardware changes.
* The SIMATIC NET driver binds immediately, and the yellow warning triangle disappears.

Verification

To confirm proper hardware communication:

Open Windows Device Manager: confirm that SIMATIC NET CP 1623 is listed under Network Adapters without warning icons.
Open Communication Settings / Set PG/PC Interface: verify that access points CP1623_1: and S7ONLINE are available and operational.
Open Station Configuration Editor: verify that CP 1623 appears in the assigned slot with a green run indicator.
Launch WinCC Runtime: verify that fault-tolerant S7-REDCONNECT connections to CPU 410-5H establish cleanly with active process data updates.

Limitations and Operational Precautions

Downgrading server BIOS should be coordinated with site IT, as older BIOS versions may lack microcode mitigations for unrelated processor vulnerabilities.
Always install the CP 1623 in a primary PCIe riser slot directly attached to CPU 1 rather than secondary expansion risers with complex PCIe bridges.
Ensure valid SIMATIC NET S7-REDCONNECT licenses (6GK1716-0HB...) are transferred via Automation License Manager. Always validate license requirements with an authorized Siemens distributor.

Engineer FAQ

Does this BIOS issue affect Siemens Industrial PCs?

No. Siemens IPCs (IPC547D, IPC647D, IPC847D) use Siemens motherboards and proprietary BIOS firmware engineered and certified specifically for CP 1623/CP 1628 cards without MMIO conflicts.

Can CP 1628 be used instead of CP 1623?

CP 1628 (6GK1162-8AA00) incorporates onboard IPsec/SSL security encryption. It shares the identical PCIe controller architecture and exhibits the same MMIO requirements on HP Gen9 servers.

What happens if I replace CP 1623 with a standard Intel server NIC?

Standard Intel NICs use Softnet S7, which supports standard S7 connections but cannot execute Hardnet S7-REDCONNECT for bumpless sub-100ms fault-tolerant communication with S7-400H CPUs.