Configuring WinCC Communication to Siemens CP 443-1 via NetPro

Configuring WinCC Communication to Siemens CP 443-1 via NetPro PC Station

This technical reference explains how to bring a WinCC SCADA station online with a SIMATIC S7-400 PLC through the CP 443-1 Industrial Ethernet communications processor using the legacy SIMATIC NetPro PC Station configuration. It covers IP address assignment rules, the OPC vs. TCP/IP driver decision, download semantics that prevent unintended CPU STOP transitions, and the OPC UA capability introduced on newer CP 443-1 firmware. Field engineers configuring STEP 7 V5.x projects against S7-400 will find the parameter tables, NetPro configuration steps, and verification checks needed to bring a WinCC channel into productive operation.

1. CP 443-1 Hardware Overview and Catalog Numbers

The CP 443-1 is the SIMATIC S7-400 module that terminates the PROFINET / Industrial Ethernet side of an AS-400 station. From a WinCC standpoint it is the IP endpoint where the SCADA station opens S7 connections (port 102 / ISO-TSAP) or — with newer firmware — OPC UA sessions (port 4840).

The WinCC side does not care which CP 443-1 sub-variant is used as long as the IP layer is reachable. The differences surface when OPC UA is required: an OPC UA server inside the CP 443-1 became available with the introduction of the 6GK7 443-1UX00 variant and was back-ported to many EX/GX modules with firmware V3.2.x or later.

2. Architecture: PC Station, CP 443-1, and WinCC Relationship

In a STEP 7 V5.x project the SCADA computer is represented by a PC Station. The PC Station contains three types of objects:

• WinCC Application (the HMI/SCADA runtime)
• OPC Server (SIMATIC NET OPC server, used by WinCC's OPC channel and by external OPC clients)
• IE General — a software-only representation of an Industrial Ethernet interface such as the CP 1613 / CP 1623 PCI/PCIe card or the Softnet IE software interface used by standard onboard NICs

The PC Station does not download configuration into the S7-400 CPU. It downloads into the OPC Server and IE General configuration database on the SCADA PC. This is the single most important conceptual point when troubleshooting the "is this safe to download?" concern.

3. Prerequisites

• STEP 7 V5.5 (or later V5.x) with SIMATIC NetPro installed on the engineering station
• SIMATIC NET PC software on the SCADA PC matching the IE interface in use (Softnet IE for onboard NICs, Hardnet IE for CP 1613 / CP 1623)
• WinCC V7.0 SP3 or later (covers WinCC V7.2, V7.3, V7.4, V7.5)
• One free IP address in the same subnet as the CP 443-1 (for the SCADA PC NIC / IE General)
• CP 443-1 firmware loaded; for OPC UA capability, V3.2.x or the corresponding firmware per release notes
• Station Configuration Editor on the SCADA PC importing the same PC Station name as configured in NetPro

4. IP Address Assignment Rules

The rules below are derived directly from the SIMATIC NET manuals referenced by Siemens support entry "SIMATIC NET Communication Manual":

1. Unique address. Each IE endpoint on the subnet must carry a unique IPv4 address. The IE General in the PC Station and the CP 443-1 must not share an IP.
2. Same subnet. Both addresses must lie in the same subnet mask. With a /24 mask (255.255.255.0), 192.168.0.1 (CP 443-1) and 192.168.0.2 (WinCC PC) communicate directly. 192.168.0.1 and 192.168.1.2 would require routing and almost always fail silently in PC Station startup.
3. PC NIC vs. IE General. The IP configured in the Windows network adapter for the SCADA PC must match the IP configured under Properties → IE General → IP Address in NetPro. Mismatches are the single most common cause of "Partner not reachable" faults from the OPC server.
4. CP 443-1 default IP. Out of the box a CP 443-1 ships with no IP and is discovered via DCP / STEP 7 — do not assume a "default CP-443-1 PN/IO address" of any specific value. The address you read in STEP 7 Hardware Configuration under CP 443-1 Properties → Ethernet Interface is the authoritative value.

5. Step-by-Step: Configuring the PC Station in NetPro

The procedure below covers the legacy STEP 7 V5.x / NetPro flow. The TIA Portal equivalent is noted at the end of the section.

5.1 Add the PC Station

1. Open the STEP 7 project containing the S7-400 station.
2. Right-click the project → Insert New Object → SIMATIC PC Station.
3. Rename the PC Station to match the Windows computer name of the SCADA PC (this is what the Station Configuration Editor on the PC will look for).

5.2 Insert WinCC Application

1. In the PC Station hardware catalog, drag WinCC Application onto slot 1 (or the next free application slot).
2. Open its properties and note the application name — this is the slot the running WinCC RT will occupy.

5.3 Insert OPC Server

1. Drag OPC Server to the next application slot.
2. This is the server WinCC's OPC channel talks to, and the one external SCADA clients connect to when sharing the OPC namespace.

5.4 Insert IE General and Assign IP

1. Drag IE General to slot 4 or higher (depending on version) — that is where SIMATIC NET expects PC-side Ethernet interfaces.
2. Double-click IE General → Properties → enter the IP Address, Subnet Mask, and (if needed) Router.
3. Select the Network dropdown — choose Ethernet (1) to bind the IE General into the same subnet you will later connect with the CP 443-1.

5.5 Insert CP 443-1 in the S7-400 Station

1. Open the SIMATIC 400 Station → Hardware.
2. From the catalog, insert the correct CP 443-1 variant matching the module on the rack.
3. Open its properties → assign IP, subnet mask, and select Ethernet (1) as the connected network.
4. Confirm the rack and slot number match the physical placement in the S7-400.

5.6 Create S7 Connection in NetPro

1. Right-click OPC Server in the PC Station → Insert New Connection → S7 Connection.
2. Choose the CP 443-1 of the S7-400 as the connection partner.
3. Set the local ID (e.g. S7_Connection_1) — this is the name WinCC's TCP/IP driver or OPC channel will reference.
4. For each connection, NetPro assigns a slot-based TSAP (Transport Service Access Point) on both ends:

5.7 Compile and Download the PC Station

1. In NetPro, click PC Station → Save and Compile (or Network → Save and Compile All).
2. Right-click the PC Station → Download to Target System.
3. In the "Select Target Station" dialog, enter the SCADA PC's IP address (it is the address bound to IE General, not the address of the CP 443-1).
4. Confirm the download. This pushes the configuration into the Station Configuration Editor and SIMATIC NET on the SCADA PC only.

6. Selecting the WinCC Channel: TCP/IP, OPC, or OPC UA

WinCC V7.x ships with multiple channel DLLs in SIMATIC S7 Protocol Suite:

For most CP 443-1 deployments, the TCP/IP channel with WinCC's SIMATIC S7 Protocol Suite is the simplest and most direct path. Named Connections are functionally similar but route everything via the OPC server, which is convenient when you also want OPC DA for third-party MES clients. OPC UA is reserved for new plants or retrofits where you want to drop the S7 Protocol Suite dependency and rely on the OPC UA server embedded in the CP 443-1 or in the WinCC station itself.

6.1 OPC UA on CP 443-1 — When to Choose It

Per the Siemens release notes (referenced by the "Siemens releases CP 443-1 OPC UA communications processor" coverage), the CP 443-1 OPC UA variant exposes an embedded UA server on port 4840 according to OPC UA specification IEC 62541. Choose OPC UA on CP 443-1 when:

• The WinCC station is multi-vendor and needs to read from S7-400, S7-1500, and third-party controllers over a single stack.
• Network policy requires authenticated / encrypted transport (Basic256Sha256 security policies).
• You want to minimize SCADA-side S7 Protocol Suite licensing and rely on standard OPC UA client channels inside WinCC Professional.

7. WinCC Variable Configuration for CP 443-1 Connections

For each logical driver selection, the WinCC tag manager then binds tags to the connection:

8. PC Station Download — Detailed Behavior

The question "is this download safe, or will it stop the PLC?" comes up regularly when commissioning engineers first encounter the PC Station. The answer is unambiguous:

• Target of the download: The PC Station download writes to Station Configuration Editor database and to the OPC server directory on the SCADA PC. It does not communicate with the S7-400 at all.
• Network path used: TCP/IP, port 102 is not opened for the PC Station download itself; NetPro uses the configured Ethernet path to the PC's SIMATIC NET Config API on a local service port (typically 102 or the Config service depending on SIMATIC NET version). It does not cross a router to the CPU.
• Effects on RUN/STOP: None. The CPU remains in its current operating mode.
• Restart required? Often yes: OPC server and IE General are services that reread configuration on service restart. After a PC Station download, restart the SIMATIC NET Configuration service (or reboot the SCADA PC) before commissioning.

9. Verification Checklist

Use the following checks in order to confirm the data path is up before going into runtime:

1. Ping from SCADA PC to CP 443-1. ping 192.168.0.1 must reply.
2. Station Configuration Editor. Open it on the SCADA PC; the WinCC Application and OPC Server components must show the configured slot numbers and a green status.
3. NetPro consistency check. Network → Check Consistency for the entire station must report 0 errors.
4. OPC Scout (S7 / OPC DA test). Launch SIMATIC NET OPC Scout and browse; the CP 443-1's connection partner must appear under the configured S7 connection.
5. WinCC Channel Diagnostics. In the WinCC Explorer, open Channel Diagnostics → SIMATIC S7 Protocol Suite → TCP/IP → Connection and confirm status "Connected / OK".
6. Tag test. Create one tag in WinCC, link it to DB1,INT0 or to a STEP 7 variable, and confirm a value change appears at 1000 ms update rate.
7. OPC UA (if used). Use the UaExpert client to browse opc.tcp://192.168.0.1:4840 and authenticate (Anonymous or Username/Password per security policy).

10. Troubleshooting Matrix

11. Migrating to TIA Portal — Equivalent Steps

For new deployments or retrofits the same engineering goal is reached via TIA Portal:

1. Insert a PC system from the device catalog.
2. Add the WinCC RT application (WinCC Professional / Comfort) and an IE general interface (CP 1623 or Softnet).
3. Add the S7-400 station with CP 443-1 hardware.
4. Use Devices & Networks → Connections to create an S7 connection between the PC station and the S7-400.
5. Compile and download the PC station configuration.

The download semantics are the same: only the SCADA PC is touched. The S7-400 stays in RUN.

12. Field-Proven Commissioning Notes

• Order of operations. Bring up the S7-400 first (CPU in RUN, CP 443-1 reachable via ping), and only then connect the SCADA PC. Reverse the order and intermittent connection faults become very hard to attribute.
• Keepalive. S7 connections on port 102 are long-lived. The CP 443-1 sends keepalive approximately every 30 s; firewalls idle-timing port 102 must be disabled or set > 60 s.
• Cycle load. Sustained update rates < 250 ms across hundreds of tags may saturate the OPC server and the CP 443-1 connection resource. Schedule a mix of 500 ms, 1 s, and 2 s updates by exception class.
• TSAP collisions. If multiple S7 connections are opened against the same CPU through the same CP 443-1, each must use a unique TSAP pair. NetPro assigns automatically but verify when copying connections.
• Router sit-down. If the SCADA PC and S7-400 live in different VLANs, the configured router (default gateway) on both the IE General and the CP 443-1 must be inside the broadcast domain of each side.
• Security layers. When OPC UA is used, Basic256Sha256 with a certificate trust list is recommended for production. Anonymous access is acceptable for engineering but must be disabled in productive operation.

13. FAQ