Configuring S7 Routing on SIMOTION D425 via Ethernet Port

Overview

The SIMOTION D425 motion controller is commonly deployed in mixed networks alongside SIMATIC S7 CPUs (e.g., CPU 315-2DP) and HMI panels (e.g., TP177B) on PROFIBUS DP. A frequent commissioning requirement is to access the entire PROFIBUS subnet from a single engineering station connected to one of the SIMOTION D's Ethernet ports. This is achieved through S7 routing, a Siemens-specific mechanism that allows a PG/PC or HMI to traverse a gateway node (the SIMOTION D) to reach stations on a different subnet.

S7 routing is a layer 7 / application-layer tunnel implemented inside the SIMOTION firmware. It is not IP routing. IP packet forwarding between Ethernet and PROFIBUS subnets is not supported by the SIMOTION D; S7 routing is the only mechanism for transparent cross-subnet access from STEP 7, SCOUT, TIA Portal, WinCC flexible, or ProSave.

Prerequisites

Before configuring S7 routing on a SIMOTION D425, verify the following:

• SIMOTION D425 controller with SINAMICS S120 integrated drive control.
• SCOUT TIA or SCOUT V4.x / V5.x (matching the controller firmware) installed on the engineering PC.
• STEP 7 V5.4 SPx or higher for S7-300 project handling. TIA Portal is supported only via the SIMOTION option package.
• WinCC flexible 2007 SP2 or later for TP177B project transfer and HMI diagnostics.
• NetPro / HW Config editor available inside STEP 7 or SCOUT (same integrated interface).
• Firmware on the SIMOTION D425: minimum V4.1 SP2 if you also route to a CBE30 (X1400). Earlier firmware limits routing to the PROFIBUS Integrated interface only.
• PROFIBUS DP network running at 12 Mbps (max for PROFIBUS DP with standard repeater topology). The 12 Mbps setting must match on the CPU 315-2DP DP master, the SIMOTION D's PROFIBUS Integrated, and any PROFIBUS slaves.
• PG/PC Ethernet interface assigned an IP address in the same subnet as the SIMOTION D's Ethernet port (e.g., 192.168.0.x / 255.255.255.0).

SIMOTION D4x5 Hardware and Interfaces

The SIMOTION D425 is a slot-in controller module for the SINAMICS S120 drive line. Its interface layout directly determines which S7 routing paths are available. Reference the SIMOTION D4x5 Commissioning Manual for the canonical port list.

The Ethernet ports IE1 (X130) and IE2 (X127) are always present. CBE30 is an optional plug-in module. Routing between these interfaces and the PROFIBUS Integrated interface is firmware-managed; the only configuration required is inside NetPro to publish the routing destination subnets.

S7 Routing Capabilities and Limits

The SIMOTION D firmware accepts S7 routing connections that are initiated on any of its Ethernet interfaces. The set of target subnets that can be reached through the routing entry is determined by the NetPro / HW Config download to the controller.

Supported S7 routing paths on a SIMOTION D425:

1. Routing from Ethernet (IE1/OP) to PROFIBUS Integrated (DP1) - default capability, available from earliest firmware releases.
2. Routing from Ethernet (IE1/OP) to PROFIBUS on the external DP master - requires that the downstream PROFIBUS subnet is configured as a routed subnet in NetPro.
3. Routing from Ethernet to a second PROFINET subnet on the CBE30 (X1400) - requires SIMOTION firmware V4.1 SP2 or higher. Without this firmware level, the CBE30 port is not exposed to S7 routing.
4. Routing between the SIMOTION D's own Ethernet interfaces - e.g., from IE1 to a separate subnet on the CBE30.

Explicitly not supported:

• IP routing from subnet A to subnet B (the controller is not an IP gateway).
• TCP/UDP port forwarding or NAT.
• Routing into DRIVE-CLiQ (drive bus is not an S7 subnet).
• Routing to PROFIBUS subnets of a third-party DP master that has not been entered in NetPro.

How S7 Routing Works at the Protocol Level

S7 routing is a Siemens-proprietary feature wrapped around the S7 communication protocol. The PG/PC (or HMI) initiates an S7 connection to a target CPU. The target CPU's MPI/DP/Ethernet address is contained in the connection setup frame. When a router node sits between PG and target, the frame is extended with a routing header that lists each hop (gateway address + destination subnet).

Each router node (e.g., the SIMOTION D) inspects the routing header, decrements the hop count, and forwards the frame out the correct interface. The PROFIBUS frame format is the same on the wire - the hop information is part of the S7 PDU, not the PROFIBUS telegram header. This is why a 12 Mbps PROFIBUS segment does not need any special routing configuration: the routing intelligence lives in the S7 layer.

For the SIMOTION D to accept and forward routing requests, three things must be true:

1. The NetPro project on the engineering station has a network view that includes the SIMOTION D, the downstream S7-300 CPU, and the HMI panel.
2. The destination subnet is assigned to the SIMOTION D's interface in NetPro (i.e., the subnet is "behind" the SIMOTION D from the PG's perspective).
3. The downloaded NetPro configuration to the SIMOTION D matches the active hardware topology (CPU 315-2DP, TP177B, etc., all sitting on the expected PROFIBUS segment).

NetPro Configuration Procedure

Open the SIMOTION project in SCOUT (or in STEP 7 with the SIMOTION extension), and double-click the SIMOTION D425 in the project tree. Choose Open NetPro from the context menu. The following steps configure the routing table.

Step 1 - Verify Interface Assignments

• Right-click the IE1/OP port of the SIMOTION D425 and select Properties. Confirm that the PG/PC subnet (e.g., 192.168.0.0/24) is assigned and that the IP address matches the controller.
• Right-click the PROFIBUS Integrated interface and confirm that the PROFIBUS subnet containing the CPU 315-2DP and the TP177B is selected. The baud rate must match 12 Mbps on every node.
• If a CBE30 is fitted, drag a PROFINET subnet onto its X1400 port.

Step 2 - Place the S7-300 and the HMI

From the hardware catalog, insert an S7-300 station with a CPU 315-2DP (6ES7 315-2AG10-0AB0 or later) onto the same PROFIBUS subnet. Add the TP177B (6AV6 642-0BA01-1AX1) as a PROFIBUS slave on the same subnet. Assign PROFIBUS addresses that do not conflict with the SIMOTION D's own DP address (default 2). Typical assignments:

Step 3 - Enable the PG/PC Routing Function on the IE1 Port

Select the SIMOTION D425 IE1/OP Ethernet port, then in Properties > Ethernet confirm:

• "Use router" is not required; leave the field empty or greyed out. The SIMOTION D acts as a router only in the S7 sense, not in the IP sense.
• "S7 routing" is enabled implicitly by the presence of the S7-300 station in the same project; no checkbox is required in classic NetPro.

If the IE1/OP properties dialog displays a Router field, it refers to the IP default gateway (used for IP-based services such as web server, NTP). It is not related to S7 routing. Leave it empty if no IP gateway is needed.

Step 4 - Download the NetPro Configuration

1. Right-click the SIMOTION D425 station and choose Target system > Download. Select the option Entire station to push both HW Config and NetPro data.
2. Wait for the message Download finished without error.
3. Cycle power on the controller if prompted (some firmware levels require a restart to activate routing table changes).

Step 5 - Configure the PG/PC Interface on the Engineering Station

On the PG/PC, open Set PG/PC Interface (SIMATIC). Select S7ONLINE > TCP/IP > <your Ethernet NIC>. The PG/PC must use the same Ethernet subnet as the SIMOTION D's IE1/OP port.

Important: do not use "TCP/IP (Auto)"; select the NIC explicitly so that the S7 routing entry on the SIMOTION D can address the correct physical interface.

Accessing the Downstream Devices from the PG

With the NetPro configuration downloaded, the PG can reach every node on the PROFIBUS segment through the SIMOTION D425 using S7 routing. The PG needs only the SIMOTION D's Ethernet IP address as the access point; STEP 7 / SCOUT / WinCC flexible handle the routing internally.

STEP 7 (CPU 315-2DP S7 program)

1. Open the S7 project in STEP 7.
2. Choose Accessible Nodes (or Online > Accessible Nodes).
3. In the dialog, the SIMOTION D425 appears with its Ethernet IP address; the S7-300 CPU appears as a routed node beneath it.
4. Double-click the CPU 315-2DP to go online. Block status, variable tables, and forced values are all reachable through the routed path.

SCOUT (SIMOTION D425 program)

1. Open the SIMOTION project in SCOUT.
2. Click Connect to target system.
3. SCOUT automatically uses the configured Ethernet interface and connects to the SIMOTION D directly (no routing required for the controller itself).
4. From the connected SCOUT session, use Target system > Browse to enumerate additional nodes on the PROFIBUS subnet.

WinCC flexible (TP177B project)

1. Open the WinCC flexible project for the TP177B.
2. Choose Transfer > Transfer with mode Ethernet / S7 routing.
3. Enter the SIMOTION D425's Ethernet IP address as the HMI gateway.
4. WinCC flexible encapsulates the TP177B's DP address inside the S7 routing frame and transfers the project.

ProSave (HMI backup/restore)

ProSave transfers TP/OP panel backups using a subset of S7 services. As long as WinCC flexible can route to the panel, ProSave typically can as well. The transfer mode must be set to Ethernet > S7 routing with the SIMOTION D's IP entered as the access point. The exact behavior depends on the panel's S7 communication stack; verify against the ProSave help if the backup fails.

Role of the CBE30 (X1400) and Firmware V4.1 SP2

The CBE30 is a 4-port PROFINET / Ethernet plug-in board for the SIMOTION D4x5 platform. It provides additional PROFINET interfaces (typically two PROFINET subnets, e.g., IE3 and IE4 in HW Config).

S7 routing through the CBE30 was added in SIMOTION V4.1 SP2. Before this service pack, the CBE30 was visible to PROFINET IO controllers but could not act as a routing target for S7 connections initiated on IE1. If you need to route from the engineering PC on IE1 to a PROFINET device on X1400, confirm the firmware level with SIMOTION Scout > Online > Accessible nodes > Device identification. The firmware string should read 4.1.2.x or higher; if it reads 4.1.0.x or 4.1.1.x, upgrade to a V4.1 SP2 image before attempting CBE30 routing.

When the CBE30 is fitted, the slot occupied is typically slot 1 in HW Config. The two physical PROFINET interfaces are X1400 P1 (port 1) and X1400 P2 (port 2) of the CBE30 module, exposed in HW Config as separate PROFINET IO systems. Some configurations also use the second pair of ports for a second PROFINET subnet, depending on CBE30 variant (e.g., 6FC5312-0FA00-0AA0 versus 6FC5312-0FA00-0AA1).

Verification and Acceptance Test

After downloading the NetPro configuration, run the following acceptance test from the engineering station:

1. Ping test: from the PG command line, ping <SIMOTION_D_IP> should succeed. The S7-300 CPU is not directly pingable because it has no Ethernet port in this topology - ping is only a check for the IP path to the SIMOTION D.
2. Accessible Nodes: In STEP 7, run Accessible Nodes. The SIMOTION D appears as the gateway; the CPU 315-2DP and the TP177B appear as routed nodes. Their PROFIBUS addresses are shown.
3. Online S7 program download: go online with the CPU 315-2DP and read the diagnostic buffer. It should show S7 connections established from the PG/PC routed via SIMOTION D.
4. SCOUT online: connect SCOUT to the SIMOTION D. The Online > Diagnostics view should list the CPU 315-2DP under Routed stations.
5. TP177B transfer test: start a WinCC flexible transfer to the TP177B. The TP177B boots into transfer mode and accepts the project through the SIMOTION D's Ethernet port.
6. ProSave backup: run a backup to USB or network share. If the transfer initiates, S7 routing to the panel is functional.

Troubleshooting Matrix

Edge Cases and Field-Proven Caveats

• Multiple engineering stations on different subnets: each PG must use the SIMOTION D's interface in its own subnet as the access point. The SIMOTION D will route from any of its Ethernet ports, so two PGs on different Ethernet subnets can both work as long as each PG addresses the right interface.
• OPC server access via routing: SimaticNet OPC servers can use S7 routing to read the CPU 315-2DP tags. Configure the OPC partner with the SIMOTION D's IP as the access point and the CPU's PROFIBUS address in the S7 connection properties.
• PROFINET IO on the same Ethernet subnet as the PG: the SIMOTION D's IE1/OP port can host PROFINET IO directly. S7 routing is then mostly transparent: the PG addresses the IO controller on the same subnet, and the S7 routing frame is empty (zero hops). This is the normal case and explains why many engineers perceive no "routing" at all.
• Replacing a SIMOTION D: a replacement D4x5 must run the same SINAMICS version and ideally the same SIMOTION firmware. The commissioning manual explicitly notes that one SIMOTION D can only be replaced with another SIMOTION D if the SINAMICS version is preserved; this is critical for S7 routing because the NetPro download is tied to the SINAMICS S120 configuration.
• IP routing is not an option: if a customer insists on IP-level routing between the engineering subnet and the office subnet, an external IP router is required. The SIMOTION D will not perform IP routing regardless of NetPro settings.
• Firmware downgrades after commissioning: downgrading SIMOTION firmware below V4.1 SP2 on a system that uses CBE30 routing will silently break the routing path. Document the firmware version in the project notes.

Configuration Checklist

Use the following checklist to confirm a complete S7 routing setup:

• [ ] SIMOTION D425 has the latest commissioning manual on hand for reference.
• [ ] SCOUT / STEP 7 project contains SIMOTION D, CPU 315-2DP, and TP177B in a single NetPro view.
• [ ] All PROFIBUS nodes operate at 12 Mbps with addresses 1-125, no duplicates.
• [ ] IE1/OP port of SIMOTION D has a valid static IP in the PG subnet.
• [ ] PROFIBUS Integrated interface is assigned the PROFIBUS subnet containing the CPU and HMI.
• [ ] Optional: CBE30 PROFINET subnets are defined and SIMOTION firmware is V4.1 SP2 or higher.
• [ ] NetPro configuration downloaded without errors.
• [ ] PG/PC interface set to the Ethernet NIC explicitly (not Auto).
• [ ] Accessible Nodes shows all three stations (SIMOTION D, CPU 315-2DP, TP177B).
• [ ] Online functions verified for STEP 7, SCOUT, WinCC flexible, and ProSave as required.

Documentation References

For further reading and the canonical description of the routing capability, refer to the official Siemens manuals:

• SIMOTION D4x5 Commissioning Manual (PDF) - hardware layout, slot positions, and replacement rules.
• Communication with SIMOTION - Siemens ID 109749943 - FAQ entry covering the three routing options to a PG/PC or HMI through a SIMOTION D with CBE30.
• SIMOTION D - PROFIBUS Product Finder - product positioning of the SIMOTION D axis control system within the SINAMICS S120 family.