Creating Named Connections in WinCC for S7-400H Systems with CP 1613 / CP 1623

A Named Connection in WinCC is a symbolically named, pre-configured link to a SIMATIC S7 AS. For S7-400H redundant controllers it is the only way to make the WinCC runtime follow the active CPU and survive a rack failure, because the connection partner (AS) and the transport medium (H network) are decoupled from a physical interface. This article documents the end-to-end procedure for building that link, using the S7 fault-tolerant connection type, dual CP 1613 / CP 1623 cards, NetPro, the Station Configurator and the SIMATIC NET driver set.

1. Why a Named Connection, and Why for H-Systems

WinCC can address an S7 AS over a "raw" TCP/IP channel, but that channel binds a tag tree to a specific transport (e.g. ISO-on-TCP / TCP / Named Connection) and to a specific logical device on the PC. On a redundant S7-400H that is insufficient:

• CPU 0 and CPU 1 share the same project but only one is the active master at any time. WinCC must follow the master automatically.
• The H system uses two physically separate PROFINET / Industrial Ethernet subnets (H network 1 and H network 2). A standard TCP channel only references one.
• A CP 1613 / CP 1623 is a Siemens proprietary PC card with its own firmware and driver stack, not a generic NIC. It must be enabled through SIMATIC NET before it is visible to WinCC.

The Named Connection solves all three problems: it is created in NetPro of the STEP 7 project, downloaded to the AS as part of the S7 program, and the runtime configuration is exported as an XDB file that WinCC imports via the Station Configurator. At runtime, WinCC looks up the connection by symbolic name; the H system switches the active path automatically, and the CP 1613 firmware handles the link-up/link-down on each H network.

For new (TIA Portal based) H systems, the same logical model is implemented as the Named Connection in the HMI configuration of Basic / Comfort Panels and WinCC Runtime. See the official TIA documentation entry for the full reference architecture.

2. Prerequisites

2.1 Hardware

2.2 Software

3. NetPro: Creating the S7 Fault-Tolerant Connection

NetPro is the central place where STEP 7 binds a connection to a logical address and to a partner. The procedure below produces the XDB file the WinCC PC needs.

3.1 Add the PC Station to the STEP 7 Project

1. In SIMATIC Manager, open the S7-400H project.
2. Right-click the project, choose Insert New Object → SIMATIC PC Station.
3. Open HW Config of the PC station and insert the two CP 1613 / CP 1623 cards in their physical slot order. Assign each card to one of the H subnets (H network 1 / H network 2). Set the MAC and IP of each card to match the corresponding CP 443-1 on the H network side.
4. Add a WinCC Application (or OPC Server / S7 Application) to the PC station if not already present.
5. Save and compile HW Config.

3.2 Create the Named Connection in NetPro

1. Open NetPro (Options → NetPro, or open it from the project tree).
2. Click the H station (S7-400H) in the network view. The lower half of NetPro now shows the connection table of the H station.
3. Right-click an empty row and choose Insert New Connection (or click the connection icon in the toolbar). The New Connection dialog appears.
4. In the partner drop-down, select the previously created SIMATIC PC Station.
5. Set Connection type to S7 Fault-tolerant connection. This is the type that works with S7-400H redundancy.
6. Confirm with Apply / OK. NetPro now creates a connection on both the H side and the PC station side; the PC station's WinCC Application (or OPC) automatically gets a corresponding connection entry.
7. If the PC station is equipped with two CP cards (one per H subnet) and you want the runtime to use them as a redundant pair, open the properties of the PC station's connection entry and tick "Enable maximum redundancy" / "Activate redundant connection" on the connection details. This binds the single logical connection to both physical CP cards.
8. Add a second named connection (e.g. S7Connection_1, S7Connection_2) if you want to split traffic — one connection per CP card is also a valid layout.

The result of this step is a pair of connection objects in NetPro, one anchored at the H station and one at the PC station. The PC station side is what later becomes the XDB file.

3.3 Compile and Export the XDB File

1. In NetPro, choose PLC → Compile and Check All (Ctrl+F11 in some versions).
2. Resolve any errors. Typical errors: PC station component mismatch, mismatched CP index, duplicate IP / MAC.
3. Click the PC station, then choose PLC → Export Station to XDB (or right-click → Export). Save the XDB to a path the WinCC PC can access (USB stick, network share, or copy it across the engineering link).
4. Do the same for the H station if you need the AS-side XDB.

4. Station Configurator: Importing the XDB on the PC

The Station Configurator (a part of SIMATIC NET) is the only tool that registers a PC station's components with the Windows services used by WinCC at runtime. The XDB file you exported in step 3.3 is the source of truth.

1. On the WinCC PC, open Station Configurator from the Windows Start menu (Start → SIMATIC → SIMATIC NET → Station Configurator).
2. The current PC station's component list is shown. If empty, the XDB has not yet been imported.
3. Click Import Station and browse to the XDB file. The Station Configurator parses the XDB, creates the Index 1 / Index 2 / Index 3 slots, and registers the CP 1613 cards and the WinCC / OPC application with the SIMATIC NET runtime.
4. Confirm the CP indices match the physical slot order. Index 2 is typically CP 1613 #1, Index 3 is CP 1613 #2 (or vice versa). The same index must be used in the Set PG/PC Interface dialog.
5. Close the Station Configurator and re-open it to verify the configuration is persistent across a service restart.

5. WinCC Configuration: Pointing the Channel at the Named Connection

WinCC's Simatic S7 Protocol Suite exposes several channel units. For a Named Connection the channel unit is S7-Driver → Named Connections, and the connection name must match the symbolic name created in NetPro.

1. Open the WinCC Explorer of your project.
2. In the tag management, right-click SIMATIC S7 PROTOCOL SUITE and add a new connection.
3. In the connection properties, set:
   • Connection name: the symbolic name from NetPro (e.g. AS_H1_S7Connection_1).
   • Channel unit: Named Connections.
4. Set the address parameters (Rack / Slot of the H CPU, or leave to default; WinCC uses the connection object in NetPro, not the raw address). Set Maximum number of connections / cycle & timeout per WinCC project guidelines.
5. Repeat for the second connection if you built a 2 × CP 1613 redundant layout.

6. Logical Device Name and the "VM/" Mystery

On a properly imported PC station, the dropdown Logical device name in the WinCC connection properties should list the CP indices exported by NetPro, for example:

CP_H1_1:   (CP 1613 #1)
CP_H2_1:   (CP 1613 #2)
S7ONLINE:  (default, ISO Ethernet)

If the dropdown shows only VM/, the cause is almost always one of the following:

7. PG/PC Interface and Configuration Console

Two Windows-level dialogs are involved and frequently confused:

7.1 Set PG/PC Interface

This is the Windows control panel applet (Start → Control Panel → Set PG/PC Interface) that decides which CP index is used for the S7ONLINE access point. After importing the XDB, set:

Access Point of the Application: S7ONLINE
Interface Parameter Assignment Used: CP1613(ISO) - Index 2

If the WinCC application uses a custom access point (visible in the WinCC channel diagnostic), assign that access point to the correct CP index as well.

7.2 Configuration Console (SIMATIC NET)

The SIMATIC NET Configuration Console (Start → SIMATIC → SIMATIC NET → Configuration Console) is where the CP 1613 / CP 1623 itself is configured: MAC address, IP address, subnet, PROFINET device name, and the diagnostic status of the firmware. Confirm here that both CPs are in state Running and that their link LEDs are up on the switches of H network 1 and H network 2 respectively.

If Configuration Console shows a red status on a CP, the CP will not appear in Set PG/PC Interface, the XDB import will skip it, and the WinCC dropdown will be missing the corresponding entry.

8. Dual CP 1613 / CP 1623 Redundancy: What "Maximum Redundancy" Means

On a fully redundant H system, the WINCC connection is fault-tolerant on two levels:

1. CPU redundancy: the S7-400H master switches from CPU 0 to CPU 1. The CP 443-1 pair keeps at least one of the two H networks reachable at all times. WinCC, using the S7 fault-tolerant connection type, automatically tracks the new master via the H sync mechanism and resumes communication without any user action.
2. PC-side CP redundancy: if the PC has two CP 1613 cards, one per H network, the runtime uses both for the same logical connection. The connection is "maximum redundant" in the sense that a single failure of a CP 1613, a cable, a switch, or a CP 443-1 does not interrupt the WinCC tag exchange.

To enable CPU-side + CP-side redundancy, all of the following must be true:

• STEP 7 H project compiled without errors.
• NetPro connection type = S7 Fault-tolerant connection.
• PC station has at least one CP 1613 / CP 1623 per H network.
• The Enable maximum redundancy box is ticked on the PC station's connection properties in NetPro.
• The XDB is re-imported into the Station Configurator after any change in NetPro.

9. Step-by-Step Summary Procedure

1. Build the S7-400H project in STEP 7, compile, download to both H CPUs.
2. Add a SIMATIC PC Station with two CP 1613 / CP 1623, one per H subnet. Add a WinCC Application object.
3. In NetPro, on the H station, create an S7 Fault-tolerant connection to the PC station. Tick Enable maximum redundancy.
4. Compile NetPro. Export the PC station as XDB.
5. On the WinCC PC, install SIMATIC NET, then start Station Configurator and import the XDB.
6. Open Set PG/PC Interface, assign S7ONLINE to the CP 1613 index that matches the XDB.
7. Open SIMATIC NET Configuration Console, verify both CPs are Running.
8. In WinCC Explorer, add a Named Connection to the SIMATIC S7 Protocol Suite, matching the symbolic name from NetPro.
9. Set the logical device name in the connection properties to the CP index (not VM/).
10. Compile the WinCC project, start the runtime, verify tags update in WinCC Channel Diagnosis.

10. Verification

After commissioning, the following checks confirm the Named Connection is healthy:

1. WinCC Channel Diagnosis: right-click the connection in the tag management → Channel Diagnosis. Status must be Connection established, no error, cycle time stable.
2. AS-side diagnostics: in STEP 7, PLC → Diagnostics/Setting → Operating Mode on the active CPU shows the S7 connection to the PC station as established.
3. CP 1613 diagnostics: in SIMATIC NET Configuration Console, both CPs report Running and Link up on the H networks.
4. Forced failover test: pull the Ethernet cable of CP 1613 #1. The runtime should continue with no log entries indicating a tag update interruption. Restore the cable; the second CP should return to standby without operator action.
5. CPU failover test: from STEP 7, force a switchover to the standby CPU. The WinCC connection must follow the new master without restart.

11. Troubleshooting Matrix

12. Common Pitfalls and Field Tips

• Do not skip the XDB import. WinCC will not invent the connection from the .s7p project file; it needs the XDB.
• Do not assume that the H system has redundancy on the WinCC side just because the AS is redundant. The PC must have two CPs and Enable maximum redundancy must be active.
• Do not change the IP of a CP 1613 from Windows network properties. Use the SIMATIC NET Configuration Console — changing it from the OS-level NIC settings breaks the indexed binding.
• Do not run WinCC and the STEP 7 engineering tool at the same time on the same PC station, both writing to the Station Configurator. The last writer wins; the runtime may then be unable to bind the CPs.
• Document the CP index assignment in the project. A swapped index between HW Config and the XDB is the most common source of "everything is configured, but nothing works".
• Cycle time: on a 500 ms WinCC picture cycle, the S7 fault-tolerant connection can mask a 1–2 s CPU failover; if your process can not tolerate that gap, raise the H failover priority to a level that completes in < 1 s.

13. Standards and Official References

For deeper background, refer to the official Siemens documentation set:

• WinCC V7.3 Communication Manual, section 12.5.3.4 — configuration of Named Connections: SIOS entry 102691766.
• FAQ — WinCC: how to configure a Named Connection: SIOS entry 8928931.
• FAQ — SIMATIC NET: Set PG/PC Interface and Station Configurator: SIOS entry 7028371.
• FAQ — WinCC and S7-400H communication: SIOS entry 100450795.
• TIA Portal / TIA Cloud reference — Named Connections for Basic, Comfort Panels and WinCC Runtime: TIA Cloud documentation.

14. FAQ