Configuring a Spare SIMATIC IPC for S7-400H WinCC RedConnect

1. Problem Definition: Spare SIMATIC IPC Fails to Communicate with S7-400H

When a spare ES/OS station is added to a SIMATIC S7-400H redundant system, the most common symptom is a WinCC runtime that starts cleanly, displays graphics, but never updates a single process value. The S7 RedConnect Diagnostic shows a reduced connection set instead of the full set present on the reference IPC. The TCP/IP channel unit shows a VM logical device name with no drop-down, indicating that the Windows access point is not bound to a CP 1623.

Reference case from the field: an S7-400H ES/OS station pool of three SIMATIC IPC 6AG4104-2CA32-1FC0 units. A fourth unit with order number 6AG4104-3DA32-1FC0 is on hand as a hot spare. The two CP 1623 PCIe cards are pulled from an old unit and installed in the spare. The WinCC project folder is rebuilt on the spare, the XDB file is exported from STEP 7 and imported, the runtime is started, and the result is zero process values. The S7 RedConnect Diagnostic on the new IPC lists connections #1, #4, #5, #6, #7 only; the reference IPC shows #1 through #7.

This is a configuration problem, not a hardware problem. The CP 1623 modules are detected, the drivers are loaded, and the WinCC project loads. What is missing is the binding between the WinCC connections and the SIMATIC NET transport, which is performed by the Component Configurator and the PG/PC Interface (Configuration Console).

2. Hardware Verification: SIMATIC IPC and CP 1623 Compatibility

2.1 Part-Number Comparison

The -1FC0 image option suffix is consistent between the two MLFBs, so the application bundle is the same. Where the base MLFB differs (the -2 vs -3 prefix in the example), confirm that:

1. Both units are approved for WinCC ES/OS operation under the same image-option code
2. Both have the same number of usable PCIe slots for the CP 1623
3. The BIOS and chipset driver are not interchangeable — a disk image from one will not boot the other

2.2 CP 1623 Mechanical and Driver State

On the spare IPC, verify before any software work:

• Both CP 1623 PCIe cards are fully seated and the retention brackets are screwed down
• Windows Device Manager shows two SIMATIC CP 1623 entries under Network adapters with no warning icons
• The SIMATIC NET PC software version on the spare matches the WinCC version in use
• The CP 1623 MAC addresses are noted; these are unique per card and will differ from the reference IPC's CP 1623 MACs

3. CP 1623 Driver and Firmware Installation

Use the SIMATIC NET PC software DVD or the WinCC installation media that matches the project. Procedure:

1. Insert the SIMATIC NET PC software DVD that matches the WinCC version in use. Typical pairings: WinCC V7.3 with SIMATIC NET V8.2; WinCC V7.4 with SIMATIC NET V8.2 SP1 or V14; WinCC V7.4 SP1 with SIMATIC NET V14 SP1.
2. Launch setup and select Install.
3. Accept the license terms.
4. In the component selection, ensure CP 1623, S7 RedConnect, and the Configuration Console are all selected.
5. Complete the installation. The installer registers the SIMATIC NET configuration service and the CP 1623 driver, and adds the Set PG/PC Interface and Component Configurator shortcuts.
6. Restart the IPC. After reboot, open Start → SIMATIC → SIMATIC NET → Communication Settings and confirm both CP 1623 instances appear with their MAC addresses.

4. S7 RedConnect Configuration Prerequisites

S7 RedConnect is the WinCC channel that handles redundant S7-400H communication. The channel uses two physical CP 1623 paths (one to each H-CPU / plant subnet) and provides failover at the application level. For S7 RedConnect to start successfully, all of the following must be in place:

• A valid XDB file from SIMATIC Manager or STEP 7, containing all S7 connections defined in the H-station's S7 program
• A configured WinCC channel of type S7 RedConnect with the same number of logical connections as the XDB
• The Component Configurator must have downloaded each connection to a specific channel unit and logical device
• The PG/PC interface access point S7ONLINE must point to a CP 1623 (not to the Windows TCP/IP stack)

If any of these four items is missing, WinCC Runtime starts, graphics display, and no data flows. The S7 RedConnect Diagnostic is the single best place to confirm what is registered.

5. PG/PC Interface (Configuration Console) Setup

The PG/PC Interface (Configuration Console) is where the OS resolves logical access points to physical devices. For a redundant IPC with two CP 1623, configure the access points as follows.

5.1 Access Point Assignment

Open Control Panel → Set PG/PC Interface (Windows 7 and earlier) or Start → SIMATIC → SIMATIC NET → Configuration Console (Windows 10 and later). Under Application Access Point, select each access point in turn and assign it to a CP 1623. Never assign an S7 access point to the Windows TCP/IP stack — this is the root cause of the VM placeholder symptom in the source case.

5.2 Diagnosing the Wrong Logical Switch

The source case shows the spare IPC with the TCP/IP sub-channel of the S7 Protocol Suite showing the logical switch set to VM with no drop-down menu. VM is the virtual-machine placeholder used by SIMATIC NET when no CP 1623 logical device is bound to the access point. A healthy configuration must show CP_H1_1: (or another CP 1623 logical name) with a drop-down listing both CP 1623 instances.

To fix this:

1. Open the Configuration Console
2. Select the access point used by the TCP/IP channel
3. Change the Assigned mode to a CP 1623 (the field lists both detected cards)
4. Click Update so the CP 1623 logical name propagates to the WinCC channel's logical device list
5. Repeat for the S7 RedConnect access point
6. Close the Configuration Console

After this change, re-open the WinCC channel unit dialog for the TCP/IP and RedConnect sub-channels. The Logical Switch / Logical Device Name parameter will now offer the CP 1623 logical devices in the drop-down.

6. WinCC S7 Protocol Suite Channel Configuration

The S7 Protocol Suite is the WinCC channel driver. It exposes multiple sub-channels: MPI, PROFIBUS, TCP/IP, ISO-on-TCP, and S7 RedConnect. For an S7-400H OS, the production sub-channel is S7 RedConnect; TCP/IP is sometimes used for engineering access or for OS-to-OS data exchange.

Each sub-channel is configured under WinCC Explorer → Variables → S7 Protocol Suite → [Sub-channel] → Connection. Right-click a connection to edit its properties.

6.1 Connection Configuration in the S7 Protocol Suite

If connections #2 and #3 are missing after the XDB import on the new IPC, the two most likely causes are:

1. The Component Configurator has not been opened since the XDB import — WinCC only registers connections that have been activated by the Component Configurator's Download to Target System action.
2. The XDB import succeeded but the logical device name remains VM — the connections exist in the WinCC project tree but are not bound to a physical path, so the runtime cannot instantiate them.

Re-open the Component Configurator, click Download to Target System (or Update), and watch the S7 RedConnect Diagnostic. The missing connections reappear after this step.

7. Component Configurator: Download Connection Lists

The Component Configurator (Start → SIMATIC → WinCC → Component Configurator) is the bridge between the WinCC connection definitions and the SIMATIC NET transport. For each connection in the S7 RedConnect sub-channel, it writes a corresponding entry to the SIMATIC NET database so that the S7 RedConnect service can establish the redundant S7 connection at runtime.

Steps for the spare IPC:

1. Close WinCC Explorer and stop WinCC Runtime.
2. Open the Component Configurator.
3. Click Read from Target System to read the existing PC station configuration. The left-hand pane populates with the IPC's components — typically two CP 1623 modules and one WinCC application.
4. Verify that both CP 1623 modules and the WinCC application appear with green check marks. A yellow or red marker indicates a configuration inconsistency that must be resolved before downloading.
5. Click Download to Target System to push the WinCC connection list down to the PC station. This is the critical step — it generates the S7 RedConnect runtime connection entries.
6. Restart the S7 RedConnect service from services.msc (or simply reboot the IPC).

After the download, the S7 RedConnect Diagnostic will list all imported connections. The number of connections listed must match the number of connections defined in the S7 program and imported via the XDB.

7.1 Why Connections #2 and #3 Disappear

The source case shows the new IPC missing connections #2 and #3 in the S7 RedConnect Diagnostic. This is consistent with the Component Configurator not having been opened since the XDB import. The XDB file only adds the connection definitions to the WinCC project tree; the runtime instances are created by the Component Configurator's Download to Target System action.

If the connections still do not appear after the Component Configurator download, check the following in order:

• The XDB file is from the same STEP 7 project that the OS connects to
• The XDB import covered all connections (not just a subset)
• The S7 RedConnect service account has write permission to its database folder
• The log file C:\Siemens\WinCC\diagnose\SIMATIC_S7_PROTOCOL_SUITE_01.LOG does not contain Logical device not found, VM, or connection refused errors
• Both CP 1623 IP addresses are in the expected subnets and reachable from the plant side

8. XDB File Import from SIMATIC Manager

XDB files are STEP 7 export files containing S7 connection data. The import path in WinCC is WinCC Explorer → Tools → STEP 7 Symbol Server / XDB Import. WinCC V7.0 and later use the symbol import tool for both symbols and connection data.

Procedure for the spare IPC:

1. On the engineering station (or directly on the IPC if STEP 7 is installed), open SIMATIC Manager.
2. Open the S7-400H project.
3. Select the OS that this IPC represents (for example OS_1).
4. Choose Options → NCM S7 → Export XDB (or PC Station → Export XDB, depending on STEP 7 version) to generate the XDB file.
5. Copy the XDB file to a USB stick or a network share that the spare IPC can reach.
6. On the spare IPC, in WinCC Explorer, run the XDB import. The S7 Protocol Suite connections for the OS are updated to match the S7 program.

9. Logical Device Name and VM Switch Selection

The Logical Switch / Logical Device Name in the WinCC TCP/IP or RedConnect channel unit dialog selects which CP 1623 logical device is used for the path. The drop-down is populated from the Configuration Console. If the drop-down is empty and the field shows VM, the Configuration Console has not been updated since the CP 1623 was installed.

To populate the drop-down:

1. Open the Configuration Console
2. Confirm both CP 1623 entries exist with non-zero MAC addresses
3. Click Update on each entry
4. Close the Configuration Console
5. Re-open the WinCC channel unit dialog — the drop-down now lists the CP 1623 logical names

Once the drop-down is populated, assign the logical device name for each connection:

• For S7 RedConnect: two entries, one per CP 1623 logical name
• For TCP/IP: one entry, typically the engineering CP 1623

Save the WinCC project, open the Component Configurator, and click Download to Target System. The S7 RedConnect Diagnostic will then show the new logical device bindings.

10. S7 RedConnect Diagnostic Verification

S7 RedConnect Diagnostic is the runtime monitor for the S7 RedConnect channel. Open it from Start → SIMATIC → WinCC → S7 RedConnect → S7 RedConnect Diagnostic.

The diagnostic window lists every S7 RedConnect connection with status indicators:

The source case shows the new IPC missing connections #2 and #3. After Component Configurator download and Configuration Console update, the diagnostic should list all 7 connections (matching the old IPC). If the count is still short, revisit Section 7.1 in order.

10.1 Log File Reference

The first place to look when S7 RedConnect fails is the log file C:\Siemens\WinCC\diagnose\SIMATIC_S7_PROTOCOL_SUITE_01.LOG (and any rotated siblings with higher index). Common error messages and their meaning:

11. Replicating the Reference IPC Configuration

To bring the spare IPC to a known-good state, replicate the reference IPC's full configuration systematically.

11.1 Computer Identity

• Same Windows computer name as the reference IPC
• Same Windows user accounts and passwords
• Same domain or workgroup membership
• Same regional and locale settings (affects date/time parsing in archives)

11.2 Network Identity

• Same OS station IP address (if used in the project)
• Same CP 1623 IP addresses for both subnets (subnet 1 and subnet 2 must match the reference)
• Same subnet masks, default gateways, DNS servers
• Same Windows firewall rules (S7 RedConnect uses specific TCP/UDP ports; open the same exceptions as the reference)

11.3 WinCC Project

• Copy the complete WinCC project folder from the reference IPC (or restore from a project backup). Do not rely solely on the XDB file — the XDB updates S7 connection definitions, but other channel parameters, archive configurations, and tag links remain in the project folder
• Verify the project opens in WinCC Explorer with the same number of connections, tags, and screens as the reference

11.4 Component Configurator

• Open the Component Configurator on the spare
• Read from Target System should match the reference (two CP 1623, one WinCC application)
• Download to Target System pushes the S7 RedConnect connections to the SIMATIC NET database

11.5 PG/PC Interface

• S7ONLINE → CP 1623 (logical index 1)
• S7ONLINE_RED → CP 1623 (logical index 2)
• All other access points left at default unless the reference shows otherwise

11.6 Topology Diagram

12. Verification and Acceptance Test

Run the following checks on the spare IPC before declaring it production-ready. Each row is a binary pass/fail; do not waive any item.

If any test fails, revisit the corresponding earlier section. The most common failure point in the source case is the Component Configurator download step, which is required for the S7 RedConnect connections to be registered with the SIMATIC NET service.

13. Field-Commissioning Notes

Field-proven points that shorten spare-IPC replacement work:

• The two CP 1623 MAC addresses are unique to each card. After moving CP 1623 modules from the old IPC to the spare, the SIMATIC NET configuration retains the new MAC addresses. The Configuration Console must be re-opened and the new MACs accepted.
• If both the spare and the reference IPC are powered on simultaneously on the same plant network with the same computer name and IP, the result is a network conflict and unpredictable behavior. For initial commissioning, disconnect the reference IPC from the plant network, or commission the spare on an isolated lab network.
• The S7 RedConnect service runs as a Windows service (named S7 RedConnect or SIMATIC S7 RedConnect). It can be restarted from services.msc without a full reboot — useful when verifying a connection-list change.
• The log file at C:\Siemens\WinCC\diagnose\SIMATIC_S7_PROTOCOL_SUITE_01.LOG is the first place to look when connections fail to come up. Older rotated logs use higher index suffixes.
• If the spare IPC has a different MLFB than the reference (for example the -3 prefix instead of -2 in the source case), check the WinCC version and the SIMATIC NET version compatibility list. The newer MLFB may bundle a different image option that requires WinCC V7.4 SP1 or later.
• When copying the WinCC project from the reference, copy the entire project folder — not just the .mcp file. The picture tree, archive configuration, user administration, and alarm logging configuration live in subfolders that WinCC reads at start-up.

14. Quick-Reference Checklist

1. Hardware: two CP 1623 seated, Device Manager clean, MAC addresses noted
2. Driver: SIMATIC NET PC software installed, version matches WinCC version
3. Configuration Console: S7ONLINE and S7ONLINE_RED both bound to CP 1623
4. Project: WinCC project copied from reference, opens without errors
5. XDB: exported from STEP 7 for the correct OS, imported into WinCC
6. Logical device: WinCC channel unit shows CP 1623 names, not VM
7. Component Configurator: Read from Target System clean, Download to Target System pushed
8. Runtime: S7 RedConnect Diagnostic lists all connections in green
9. Failover: both directions tested with cable pull, no tag loss
10. Acceptance: all 8 verification tests pass

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