Configuring S7 Data Set Routing for SIMATIC PDM with SIRIUS 3RW44 via External CP 443-5 in PCS 7

Configuring S7 Data Set Routing for SIMATIC PDM with SIRIUS 3RW44 via External CP 443-5 in PCS 7

When uploading configuration or switching a SIRIUS 3RW44 Soft Starter online via SIMATIC PDM V8.1 SP1 fails when routed through an external communications processor CP 443-5 Extended (6GK7443-5DX05-0XE0) on a CPU 416-2DP, the root cause is uncompiled S7 Data Set Routing (DS Routing) in NetPro or an improper communication path definition in PDM. While modern CPU 410-5H controllers manage cross-subnet routing dynamically, classic S7-400 CPUs (such as CPU 416-2DP V5.3) require complete NetPro network compilation ('Compile and check everything') downloaded to the CPU in STOP mode, sufficient communication resources allocated in CPU properties, and explicit PDM device network path assignment pointing to the CP 443-5 subnet.

Table of Contents

• Executive Summary
• S7 Data Set Routing Architecture: C-Bus Mechanics between CPU and CP 443-5
• Why CPU 410-5H Succeeds While Classic S7-400 Controllers Require Explicit Configuration
• NetPro Network S7 Routing Compilation Prerequisites
• Step-by-Step Configuration Workflow for PDM Routing via External CP
• Controller PDM Routing Capability and Hardware Prerequisite Matrix
• Verification
• Device Integration and EDD Communication Parameters for 3RW44
• Limitations and Operational Precautions
• Engineer FAQ
• Technical References
• Related Articles
• Related Tags

Executive Summary

In SIMATIC PCS 7 process plants, engineers parameterize intelligent field equipment—such as the Siemens SIRIUS 3RW44 Soft Starter—using SIMATIC PDM (Process Device Manager). Rather than physically connecting an engineering cable to each motor starter on the plant floor, engineers utilize S7 Data Set Routing (Record Routing) over the Industrial Ethernet plant bus, through the automation controller, across the communication backplane (C-Bus), and onto the PROFIBUS DP line governed by an external CP 443-5 Extended (6GK7443-5DX05-0XE0). A frequent engineering roadblock occurs when this routing configuration functions flawlessly on modern CPU 410-5H systems but fails completely on classic controllers such as the CPU 416-2DP (firmware V5.3), preventing PDM from switching online or uploading device parameters. This article explains the internal S7 routing architecture and provides verified solutions.

S7 Data Set Routing Architecture: C-Bus Mechanics between CPU and CP 443-5

S7 Data Set Routing allows engineering stations to transmit acyclic parameter telegrams (read/write data record calls) across multiple subnets:

• The Communication Path: Engineering PC (Industrial Ethernet) -> CPU Communication Interface -> S7-400 Communication Bus (C-Bus) -> CP 443-5 Extended -> PROFIBUS DP Cable -> SIRIUS 3RW44 Soft Starter.
• Acyclic Data Record Protocol: PDM uses acyclic SFB52 (RDREC) and SFB53 (WRREC) protocol packets encapsulated within S7 routing frames.
• Routing Table Requirement: For the CPU to bridge packets from Ethernet to the external CP, the CPU operating system must hold an active System Data Block (SDB) routing table that maps the unique Subnet IDs of both networks.

Why CPU 410-5H Succeeds While Classic S7-400 Controllers Require Explicit Configuration

The performance difference between controller generations stems from internal buffer management:

• SIMATIC CPU 410-5H: Features high-speed internal multi-channel communication coprocessors with unified memory. It dynamically allocates communication jobs and automatically compiles routing tables upon project compilation.
• Classic SIMATIC S7-400 (CPU 416-2DP): Operates with fixed communication resources partitioned across MPI, DP, and external CPs. If the SDB routing tables are not generated via NetPro or if communication connection resources are restricted, the CPU silently drops acyclic routing packets destined for external CPs.

NetPro Network S7 Routing Compilation Prerequisites

To establish valid routing tables in classic S7-400 controllers:

1. Unique Subnet IDs: In HW Config and NetPro, the Industrial Ethernet network and the PROFIBUS DP network attached to the CP 443-5 must have unique S7 Subnet IDs (e.g. 007A-0001 and 007A-0002).
2. Global Network Compilation: Engineers cannot simply save HW Config. They must open NetPro, select Network -> Save and Compile, and select Compile and check everything to calculate cross-subnet gateway routing paths.
3. Full STOP Download: SDB routing tables cannot be updated online; they must be downloaded to the CPU in STOP mode.

Step-by-Step Configuration Workflow for PDM Routing via External CP

To restore PDM online communication with the SIRIUS 3RW44 via CP 443-5 on a CPU 416-2DP:

1. Verify HW Config Subnet Assignments:
   * Open HW Config for the AS station.
   * Confirm that the CPU or Ethernet CP is connected to the Industrial Ethernet subnet.
   * Double-click the CP 443-5 Extended (6GK7443-5DX05-0XE0). Under properties, ensure the DP interface is operating in DP Master mode and connected to the dedicated PROFIBUS DP subnet.
2. Compile Global Routing in NetPro:
   * Open NetPro in SIMATIC Manager.
   * Select Network -> Save and Compile.
   * Choose Compile and check everything and verify 0 errors.
   * Download network connections and hardware configuration to the CPU in STOP mode.
3. Configure Communication Path in SIMATIC PDM:
   * In SIMATIC Manager, switch to the Process Device Plant View.
   * Locate the SIRIUS 3RW44 device.
   * Right-click the device and select Object Properties -> Communication.
   * Verify that the assigned gateway path specifies the CP 443-5 Extended and matching PROFIBUS DP address, not the CPU's internal DP port.
4. Switch Online in PDM: Open the device in SIMATIC PDM and select Device -> Connect to Device.

Controller PDM Routing Capability and Hardware Prerequisite Matrix

The following table compares S7 data set routing capabilities across controller families:

Verification

Confirm that PDM online routing functions accurately:

1. PDM Online Status Check: In SIMATIC PDM, open the SIRIUS 3RW44 device view. Click Device -> Connect to Device. Verify that the status bar transitions to Online (green indicator) without communication timeout faults.
2. Configuration Upload: Select Device -> Upload to PG/PC. Confirm that parameter datasets (motor rated current, starting class, current limit percentages) are read successfully from the 3RW44 into PDM.
3. Diagnostic Status: Open the PDM Diagnostics tab. Confirm that measured operating current and device status words update live.

Device Integration and EDD Communication Parameters for 3RW44

When parameterizing 3RW44 soft starters:

• EDD Version Matching: Use SIRIUS Soft Starter EDD V3.0 (or matching certified release) imported via Device Integration Manager (DIM).
• Baud Rate Constraints: The CP 443-5 Extended supports standard PROFIBUS speeds (up to 12 Mbps); verify that bus termination resistors on the physical segment are powered and switched ON at both ends.

Limitations and Operational Precautions

Downloading compiled NetPro routing tables to a CPU 416-2DP requires transitioning the controller to STOP mode. Never attempt to download network configurations to an active automation controller without an approved plant shutdown window.

When procuring CP 443-5 Extended communications processors, S7-400 CPUs, or PDM communication licenses, all hardware and software MLFBs must be validated against official Siemens catalogs and confirmed through an authorized Siemens distributor quotation.

Engineer FAQ

Does CPU 416-2DP V5.3 support S7 routing?

Yes. Siemens specifications confirm that CPU 416-2DP supports S7 data set routing from firmware V5.1 onwards.

Why did the CPU 410-5H work without extra steps?

The CPU 410-5H features advanced communication firmware that automatically optimizes routing paths and communication buffers during compilation.

Can PDM communicate with 3RW44 using standard GSD files?

GSD files allow cyclic process control in CFC, but acyclic parameterization and detailed diagnostics in PDM require an Electronic Device Description (EDD).

What happens if S7 Subnet IDs are identical in NetPro?

If two subnets share the same Subnet ID, the routing engine cannot differentiate between networks, and S7 routing packets are dropped.

Technical References

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