Configuring S7-RedConnect for S7-400H with CP1613 and WinCC V6.2

1. Problem Context and System Topology

A SIMATIC S7-400H configuration requires a redundant PC station when the supervisory layer (WinCC) must survive a failure of one CPU, one CP443-1 backplane module, or one Industrial Ethernet subnet. The reference topology under discussion contains the following components:

• Automation level: one S7-400H rack with two CPUs (e.g., 6ES7417-4HT14-0AB0) and two CP443-1 Ethernet communication processors, one on each redundant subnet.
• Supervisory level: one SIMATIC PC station running WinCC V6.2 SP2 on Windows XP Professional SP2.
• PC-side hardware: one or two CP1613 PCI cards (6GK1 161-3AA0x), depending on the redundancy class chosen.
• Software layer: S7-RedConnect, which is mandatory because the PC must maintain a logical S7 connection to the H-system regardless of which CP443-1 or which subnet is currently active.

Without S7-RedConnect, a single ISO-on-TCP / S7 connection from the PC is bound to one CP443-1 and will drop when that CP fails or when the subnet attached to it is disrupted. The H-system internally fails over to the standby CPU within roughly 100 ms to a few seconds, but the PC has no native awareness of that event and its OPC / S7 channel stays disconnected. S7-RedConnect closes this gap by holding two parallel S7 connections in the background and switching the active one transparently.

2. S7-RedConnect: Function, Licensing, and Redundancy Role

S7-RedConnect is a SIMATIC NET software package that provides a fault-tolerant S7 communication layer between a Windows-based application (WinCC, WinAC, OPC server, custom SAPI-S7 client) and an S7-400H or S7-400F/FH automation system. Architecturally, it sits between the S7-1613 / SAPI-S7 interface and the WinCC channel DLL.

Licensing model. S7-RedConnect is sold as a Powerpack on top of the base S7-1613 license:

1. S7-1613 – base license, required on every CP1613-equipped PC station that talks S7 to a SIMATIC S7 PLC.
2. POWERPACK S7 REDCONNECT – upgrade license that enables the redundant mode. It is sold per PC station, not per connection.

Without the Powerpack, the CP1613 can still establish a single (non-redundant) S7 connection to one CP443-1; with the Powerpack installed, the same PC station can hold up to two parallel S7 connections (one to each CP443-1) and switch between them within typically less than one second of detecting a partner failure.

3. CP1613 Hardware: Single vs Dual Configuration

The CP1613 is a PCI / PCI-104 card from the SIMATIC NET family that handles ISO-on-TCP, TCP, UDP, and PROFINET CBA with a dedicated on-board processor, offloading the protocol stack from the host CPU. Relevant catalog numbers for this generation:

• 6GK1 161-3AA01 – CP1613, PCI 32-bit, 10/100 Mbit, early version.
• 6GK1 161-3AA02 – CP1613, PCI 32-bit, 10/100 Mbit, hardware revision with improved RJ45 latch.
• 6GK1 161-3AA03 – later firmware variant with extended diagnostic counters.

Driver support on Windows XP SP2 is bundled in SIMATIC NET PC Software Edition 2006 or later (2007 / 2008 SPx). CP1613 is not a Plug-and-Play device; it must be enabled in the BIOS for legacy IRQ resources and the SIMATIC NET install must complete before the card is recognized by the Station Configuration Editor.

3.1 Single CP1613 (Simple Redundant Connection)

In this mode one CP1613 is bound to a managed switch that is physically connected to both H-subnets. The PC runs two logical S7 connections, both routed through the same physical CP1613, both pointing to the same MAC address but to different remote IP endpoints (one CP443-1 IP per subnet). When the standby CP443-1 takes over, S7-RedConnect simply re-resolves the connection.

Pros: cheaper (one CP1613, one Powerpack).

Cons: any failure of the CP1613 itself, of its RJ45 cable, or of the managed switch simultaneously takes down both logical connections. There is no failover path for a PC-side hardware fault.

3.2 Dual CP1613 (Full Redundant Connection)

In this mode two CP1613 cards are installed in the PC, each one connected to a different H-subnet. S7-RedConnect configures two parallel S7 connections, one per CP1613, and switches over not only when the H-system fails over but also when a CP1613, a cable, or a switch port fails.

Pros: full hardware redundancy end-to-end; recommended for plants classified SIL 2/3 or where the HMI is the primary operator interface.

Cons: second CP1613 (slot, IRQ, cable, switch port) and slightly higher load on the host CPU.

4. CP443-1 Integration in the H-System Backplane

Each H-CPU rack typically contains one CP443-1 per redundant subnet. Common catalog numbers used with S7-400H in this era:

• 6GK7 443-1EX11-0XE0 – CP443-1, 10/100 Mbit, ISO/TCP/UDP, 8 S7 connections (older firmware).
• 6GK7 443-1EX20-0XE0 – CP443-1 with extended connection count (32), required for larger WinCC tag populations.
• 6GK7 443-1GX20-0XE0 – CP443-1 Advanced, used in PCS 7 V6/V7 environments.

Each CP443-1 is configured with a fixed IP address on its own subnet:

The H-system redundancy uses fiber-optic sync modules (e.g., 6ES7 960-1AA04-0XA0) for hot-standby synchronization between the two CPUs; that path is independent of the Ethernet subnets. The H-system to PC-station redundancy is purely an Ethernet concern and is handled by S7-RedConnect.

5. Software Prerequisites and Compatibility Matrix

Three compatibility questions must be answered before installing anything:

1. Which SIMATIC NET / S7-RedConnect version supports WinCC V6.2 SP2?
2. Which S7-RedConnect version supports the installed CP1613 firmware?
3. Which S7-RedConnect version supports Windows XP Professional SP2?

The authoritative compatibility matrix is the Siemens Support entry 18734363 – "Compatibility Tool for Automation and Drive Technology". Always cross-check against the matrix inside the latest SIMATIC NET PC Software DVD sleeve, because individual service packs can shift compatibility one row down.

The S7-RedConnect manual and the Powerpack installation guide are bundled in PDF form on the SIMATIC NET installation DVD in the folder \Doc\S7RedCon\. The standalone English manual is also referenced as S7-RedConnect – Function Manual, edition 06/2006 (printed matter identifier A5E00371753-01). For installations where the DVD is no longer available, Siemens provides the document for download through the Siemens Support portal under the keyword "S7-RedConnect".

6. Operating System Constraints: Windows XP SP2

Windows XP Professional SP2 (32-bit only) is the lowest common denominator that still works with both WinCC V6.2 SP2 and S7-RedConnect V6.x. Hard constraints:

• Architecture: x86 only. CP1613 drivers on this stack were never released for x64.
• DEP (Data Execution Prevention): SIMATIC NET 6.x and S7-RedConnect 6.x rely on opt-out DEP behavior. After installing SIMATIC NET, verify that the S7-RedConnect service executable S7rcs.exe is excluded from DEP via System Properties → Advanced → Performance → Data Execution Prevention → Add.
• Windows Firewall: the SIMATIC NET install opens TCP/UDP 102, 34964, 34965 and ISO-over-TCP ports. The XP SP2 firewall must be either disabled in service mode or configured with explicit allow rules for s7oiehsx.exe, S7rcs.exe, and SIMATIC NET Configuration.
• DCOM and RPC: WinCC channel diagnostics and OPC browse use DCOM. On XP SP2, DCOM ports are dynamically assigned and the firewall tends to block them. Siemens' recommendation is to set HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\Internet\Ports to a static range and allow that range.
• User Account Control: not applicable to XP SP2.

7. WinCC V6.2 SP2 Compatibility Notes

WinCC V6.2 SP2 is the second service pack of WinCC V6.2 and ships with the SIMATIC WinCC V6.2 SP2 DVD (order number 6AV6 381-1BM06-2EX0). Compatibility facts:

• Requires STEP 7 V5.3 + SP2 or higher for the project integration. STEP 7 V5.4 SP5 is the recommended pairing at this OS level.
• Connects to S7-400H only via the SIMATIC S7-Protocol Suite channel DLL SIMATIC S7 Protocol Suite.chn.
• The channel's TCP/IP unit uses the S7-RedConnect driver when one is installed; otherwise it falls back to the standard S7-1613 single-connection mode.
• Maximum tag count for a single PC station at this version is 64 000 power tags / 256 000 internal tags, but practical throughput on Windows XP SP2 with CP1613 is limited to roughly 1500 tags/s for cyclic reads.

8. Installation and Configuration Procedure

The following step-by-step sequence must be followed in order. Skipping steps is the single most common cause of "S7-RedConnect missing in WinCC" symptoms.

1. Prepare the OS. Install Windows XP Pro SP2 with all critical updates up to the security baseline your plant accepts. Set the computer name to a stable value (e.g., HMI-PC-01) – it must not change after the Station Configuration Editor is built.
2. Set DEP exception in advance. Add C:\Siemens\Automation\S7-RedConnect\bin\S7rcs.exe to the DEP exception list before any SIMATIC software is installed.
3. Disable the XP firewall temporarily for the install. Re-enable with explicit rules after commissioning.
4. Install STEP 7 V5.4 SP5. Required for SIMATIC Manager and for editing the PC station hardware configuration.
5. Install SIMATIC NET PC Software 6.3 (or SIMATIC NET 2007 if you plan to move to WinCC V7). Choose Custom and explicitly select the components: SIMATIC NET PC Software, S7-1613 Driver, Configuration Console, S7-RedConnect, OPC Scout V10.
6. Install the POWERPACK S7-RedConnect license key. The Powerpack is delivered on a license USB stick (color red) with the part number 6GK1 716-1CB10-3AA0 (or similar). Run Automation License Manager and transfer the key to the local license container.
7. Install WinCC V6.2 SP2. Insert the WinCC DVD; the setup detects the S7-RedConnect driver and registers the SIMATIC S7 Protocol Suite channel with redundant capability enabled.
8. Configure the PC station. Launch the Station Configuration Editor. Insert an OPC Server or WinCC Application on Index 1 and one or two CP1613 modules on the next indices. Set the IP address(es) and the associated Industrial Ethernet subnet(s).
9. Edit the PC station in SIMATIC Manager. Open the PC station in HW Config. Drag the CP1613 from the hardware catalog (SIMATIC PC Station → CP Industrial Ethernet → CP1613) into the slot. For dual-CP1613, repeat for slot 2.
10. Configure S7 connections. In NetPro, add two S7 connections from the OPC server (or WinCC application) to each CP443-1 of the H-system. Mark each connection as redundant partner of the other – this is what S7-RedConnect recognizes at runtime.
11. Compile and download the PC station. In NetPro, choose PC Station → Compile, then Download to Target System. The PC-side configuration is written into the registry, not to a CF card.
12. In WinCC, open the SIMATIC S7 Protocol Suite. Create a new TCP/IP connection, select the connection name that matches the redundant pair configured in NetPro. The redundancy is automatic – WinCC itself does not need to know that two physical connections exist.

9. Verification and Diagnostics

Verification is performed in three layers, from hardware to application.

9.1 Hardware and Link Layer

• Open Configuration Console (Start → SIMATIC → SIMATIC NET → Configuration Console). Verify that each CP1613 shows Diagnostic = OK, Link = Up, and the configured mode matches the active mode (e.g., Configured mode = Automatic, Current mode = Automatic).
• Use ping -t <CP443-1 IP> from a command prompt to confirm Layer 3 reachability on each subnet. A constant <1 ms response with 0 % loss is the healthy baseline.

9.2 S7-RedConnect Service Layer

• Open the S7-RedConnect Diagnostic tool from the Start menu. Both configured connections should show Status = established (active) and established (standby).
• In the Windows Event Viewer under Application, source S7rcs, look for event ID 1 (started) and event ID 4 (connection switched) – the latter must appear exactly once during a controlled failover test.

9.3 WinCC Channel Layer

• In WinCC Explorer open Tag Management → SIMATIC S7 Protocol Suite → TCP/IP. Right-click the connection and choose Connection Status. Healthy state: Established.
• Force a connection test by reading a known tag, e.g., a Merker word MW100 with the value 16#0001 when CPU0 is master and 16#0002 when CPU1 is master.

1. Pull the patch cable on CP443-1 of the active CPU.
2. Power-cycle the active CPU.
3. Pull the patch cable on CP1613 #1 (if dual).
4. Stop the S7-RedConnect service and start it again.

10. Troubleshooting Matrix

11. Document Set and References

The following Siemens documents are required reading for any engineer commissioning this configuration. They are not optional.

• Compatibility Tool for Automation and Drive Technology – Entry 18734363. Live matrix of SIMATIC NET, S7-RedConnect, CP1613 firmware, WinCC, and STEP 7 compatibility.
• S7-RedConnect – Function Manual and Release Notes – Entry 20710190. Functional description, parameter list, and known restrictions.
• SIMATIC Fault-Tolerant Systems S7-400H manual (entry identifier on the S7-400H Automation Systems manual CD, 6ES7 498-7HA00-8BP0 or successor). Sections 10–12 cover PC station integration.
• SIMATIC NET PC Software S7-RedConnect – Installation and Commissioning, edition 2006 (A5E00371753-01). Bundled on the SIMATIC NET DVD under \Doc\S7-RedConnect\S7RedCon_e.pdf.
• SIMATIC NET Configuration Console – Online Help. Embedded CHM help, opened from Start → SIMATIC NET → Documentation.
• WinCC V6.2 SP2 Information System. Local help opened from WinCC Explorer → Help menu; sections Communication → SIMATIC S7 Protocol Suite cover the redundancy behavior exposed to tag management.

12. Key Take-aways

• S7-RedConnect is the only supported way for a WinCC PC station to talk redundantly to an S7-400H. It is a software layer, not a separate physical channel.
• One Powerpack license covers one PC station regardless of whether one or two CP1613 cards are installed.
• Single CP1613 is cheaper but exposes a single point of failure on the PC side; dual CP1613 is the fully redundant option.
• For WinCC V6.2 SP2 on Windows XP SP2 the correct pairing is SIMATIC NET 6.3 + S7-RedConnect V6.3, confirmed in entry 18734363.
• Install order matters: STEP 7 → SIMATIC NET → S7-RedConnect Powerpack → WinCC. Reverse order produces a non-redundant fallback that compiles but does not switch over.
• Acceptance testing must exercise every failure path explicitly; passive "it works" commissioning leaves latent bugs in the failover code path.