Resolving CP 1613 / CP 1623 Initialization Failures When Configuring Simultaneous MAC and IP Protocols in SIMATIC NET

When a CP 1613 or CP 1623 communications processor enters a STOP state or throws an initialization fault upon downloading a dual MAC (ISO) and IP (TCP/IP) configuration, the failure is caused by an unassigned or conflicted NDIS driver binding in Windows, an IP address mismatch between HW Config and the active adapter, or attempting to use 'Configured Mode' while the PG/PC Interface is bound to the wrong access point. To resolve this, activate the SIMATIC NET NDIS protocol in Windows Network Connections, verify static IP parameters, ensure the PG/PC Interface points to 'PC internal.local.1', and download the station via Station Configuration Editor.

Root Causes of CP 1613 / CP 1623 Initialization and STOP Errors

The CP 1613 and CP 1623 are PCI/PCIe communications processors with dedicated onboard microprocessors designed for demanding Industrial Ethernet communications in PCS 7 OS Servers and Engineering Stations. Unlike standard commercial network interface cards (NICs), these processors can operate as autonomous communications coprocessors running Layer 2 ISO and Layer 3 TCP/IP simultaneously.

However, attempting to configure both MAC and IP addresses simultaneously frequently results in the CP going into a STOP or error state during the Station Configurator download due to several architectural pitfalls:

1. Inactive SIMATIC NET NDIS Driver Binding

When a CP 1613/CP 1623 is installed, it requires two distinct driver components:
* SIMATIC NET Hardware Driver: Manages direct memory access (DMA) and ISO transport protocol execution directly on the CP hardware coprocessor.
* SIMATIC NET NDIS (Network Driver Interface Specification) Adapter: Provides the software bridge allowing the Windows TCP/IP protocol stack to communicate through the physical CP.
If the NDIS adapter binding is disabled in Windows Network Connections, or if the CP is configured in HW Config with an IP address while Windows has unconfigured DHCP or an IP conflict, the SIMATIC NET driver refuses to transition the CP from STOP to RUN.

2. Station Configuration Editor / HW Config Parameter Mismatch

In PCS 7 PC Stations, the configuration resides in two places: the STEP 7 Hardware Configuration (HW Config) and the local Station Configuration Editor (SCE). If the module index (Slot number) in SCE does not match the index assigned in HW Config, or if an IP address is enabled in HW Config but the CP was imported into SCE with only Layer 2 properties, the driver aborts the startup sequence with an internal configuration fault.

3. Misconfigured PG/PC Interface Access Point

During the initial station download, if the PG/PC Interface access point S7ONLINE is set directly to CP1613(ISO) or CP1613(RFC1006) instead of PC internal.local.1, the download utility attempts an out-of-band overwrite of the active adapter firmware parameters, terminating the connection and leaving the card in an uninitialized STOP state.

Operating Mode Matrix - ISO vs TCP/IP on CP 1613 / CP 1623

Industrial Ethernet communications cards in PCS 7 support different protocol combinations based on the operational requirements of the automation plant:

Pure Layer 2 ISO Mode (MAC-based)

Used primarily for S7-REDCONNECT fault-tolerant connections to redundant S7-400H / CPU 410-5H controllers.
Operates entirely on the card's coprocessor using hardware MAC addressing.
Highly deterministic, immune to broadcast storms, and independent of Windows TCP/IP stack stability.
Does not require Windows IP assignment or NDIS drivers.

Simultaneous Dual Mode (ISO + TCP/IP)

Allows the same physical Industrial Ethernet cable and CP port to serve two functions:
1. Fault-tolerant ISO S7 connections to S7-400H PLCs on the Plant Bus.
2. TCP/IP communication for NTP time synchronization, network monitoring via SNMP, or diagnostic routing to intelligent field devices.
Requires the NDIS driver to be active and properly bound in Windows.
Requires exact IP and Subnet mask alignment between Windows network settings and STEP 7 HW Config.

Comparison Table - Protocol Binding Configurations

The following table compares the configuration requirements and behavioral characteristics of CP 1613 / CP 1623 under single and dual protocol operating modes.

Feature / SettingPure ISO (MAC Only)Pure TCP/IP (IP Only)Simultaneous Dual Mode (ISO + TCP/IP)Primary Use CaseFault-tolerant S7-400H Plant BusStandard terminal bus / non-redundant ASCombined Plant Bus with NTP / DiagnosticsWindows NDIS Adapter BindingNot required (Can be disabled)MandatoryMandatoryIP Address AssignmentNone (Disabled in HW Config)Static IP in HW Config & WindowsStatic IP matching in HW Config & WindowsS7-REDCONNECT SupportFull hardware accelerationNot supported for S7-400H redundancyFull hardware acceleration via ISO channelTime Synchronization MethodSIMATIC Time Sync (SICLOCK)NTP or SIMATIC ModeBoth SIMATIC Mode and NTP supportedCommon Failure SymptomMissing license in ALMDHCP conflict / unreachable subnetCard enters STOP during SCE station download

Step-by-Step Recovery and Dual-Protocol Configuration Procedure

Follow this verified recovery sequence to resolve the CP initialization fault and successfully configure simultaneous MAC and IP protocols:

Reset CP 1613/CP 1623 in Station Configuration Editor:
* Open Station Configuration Editor with administrative rights.
* Highlight the CP 1613/1623 in its slot, select Clear, or set the station to STOP.
* If the module is faulted, reboot the PC to release the locked DMA buffer.
Verify Windows Network Adapter Properties:
* Open Windows Control Panel -> Network and Sharing Center -> Change adapter settings.
* Locate the network connection associated with the CP 1613/1623 (e.g., Local Area Connection - SIMATIC NET CP 1613).
* Right-click the adapter, select Properties, and verify that:
- Internet Protocol Version 4 (TCP/IPv4) is checked.
- SIMATIC NET NDIS Protocol is enabled.
- Assign the desired static IP address and subnet mask (e.g., 192.168.1.10, 255.255.255.0). Do not use DHCP.
Configure the PC Station in SIMATIC Manager (HW Config):
* Open the PC Station in HW Config.
* Double-click the CP 1613/1623 in the virtual rack.
* Under the General tab, click Properties.
* Check Set MAC address / use ISO protocol and enter the factory MAC address printed on the card label.
* Check IP protocol is being used, assign the exact same IP address and subnet mask configured in Windows, and assign the card to the target Plant Bus Ethernet subnet.
* Save and Compile HW Config.
Set PG/PC Interface to PC Internal:
* Open Set PG/PC Interface from Control Panel or SIMATIC Manager.
* Set the Access Point of the Application (S7ONLINE) to PC internal.local.1.
* Click OK.
Download Station Configuration:
* In HW Config, select PLC -> Download to Current Module.
* Enter the exact PC Station Name as declared in the Station Configuration Editor.
* Confirm the download.
* In Station Configuration Editor, verify that the CP 1613/1623 transitions to a solid RUN state with a green checkmark.

Verification

Confirm proper dual-protocol operation using the following diagnostic methods:

Verify Station Configuration Editor Status:
* Open Station Configuration Editor. The CP module icon must display a green RUN indicator without exclamation marks or yellow warnings.
Test Layer 2 ISO Communication:
* Open SIMATIC Manager -> NetPro.
* Right-click the PC Station and select Activate / Verify Connections. Confirm that the fault-tolerant S7 connection to the S7-400H shows status Established.
Test Layer 3 IP Communication:
* Open a command prompt (cmd.exe).
* Execute ping <IP_Address_of_CP> to confirm local TCP/IP responsiveness.
* Ping other network nodes on the Plant Bus (e.g., CP 443-1 IP interface) to confirm bidirectional IP packet flow.

Limitations and Operational Precautions

Hardware Slot Number Matching: The virtual slot number of the CP in Station Configuration Editor (e.g., Slot 3) must strictly match the slot assigned in the STEP 7 PC Station HW Config. Any slot discrepancy triggers an immediate station download error.
IP Conflicts with Terminal Bus: Never assign an IP address to the CP 1613/1623 that resides within the same IP subnet as the OS Server's Terminal Bus adapter. Dual-homed OS Servers must maintain strictly separated subnets for Plant Bus and Terminal Bus to avoid IP routing confusion.
Firmware Updates: Ensure CP 1613 / CP 1623 firmware is updated to the latest revision supported by your installed SIMATIC NET PC Software version.

Engineer FAQ

Can S7-REDCONNECT fault-tolerant connections run over TCP/IP instead of ISO?

No. Fault-tolerant S7 connections (S7-REDCONNECT) between WinCC OS Servers and redundant S7-400H / CPU 410-5H controllers require the ISO protocol based on MAC addressing. S7-REDCONNECT does not support standard TCP/IP on the Plant Bus.

Why does the CP enter STOP when I select 'Configured Mode' in Station Configurator?

The CP enters STOP if there is a mismatch between the configuration downloaded from STEP 7 and the actual physical hardware, such as an incorrect MAC address, missing NDIS protocol binding, or slot index mismatch in the virtual rack.

What is the replacement for CP 1613 in modern PCS 7 systems?

The PCI-based CP 1613 (6GK1161-3AA01) is succeeded by the PCIe-based CP 1623 (6GK1162-3AA00) and CP 1628 (6GK1162-8AA00), which offer identical protocol capabilities and full hardware acceleration.

Do I need to assign a gateway address to the CP 1613 IP interface?

Only if the Plant Bus requires routing to external subnets. In standard PCS 7 architectures, the Plant Bus is an isolated, non-routed network, so the default gateway should be left blank.