S7 Routing to SINAMICS S120 via IBHnet MPI: Configuration

S7 Routing to SINAMICS S120 and G120 via IBH S7++ Link over MPI/PROFIBUS

This reference documents the end-to-end procedure to bring an engineering station online with SINAMICS S120 and SINAMICS G120 drive objects that sit on the PROFIBUS DP port of a SIMATIC S7-400 CPU, when the engineering PC is connected to the S7-400 MPI/DP interface through an IBH S7++ Link adapter. The technique is also valid for SIMOTION D4x5 controllers that share the same bus architecture. The single most important prerequisite is a fully compiled and downloaded PG/PC station in NetPro with the S7 routing tables embedded in the SDB container of the S7-400.

1. Topology Overview

The reference architecture has three logical S7 subnets joined by the S7-400 CPU acting as router:

• Subnet 1 - MPI (engineering station ↔ CPU MPI/DP port 1). The PC connects to this subnet through the IBH S7++ Link adapter on its MPI/PPI channel.
• Subnet 2 - PROFIBUS DP (CPU MPI/DP port 2 ↔ SINAMICS S120 CU320/CU310, SINAMICS G120 with CU240/CU250 control unit, SIMOTION D4x5). All drive objects are DP slaves on this segment.
• Optional Subnet 3 - PROFINET/Ethernet (CPU PN/IE port ↔ additional drives or HMI). The same routing rules apply across the PN/IE interface.

2. Prerequisites

Verify in the Control Panel "Set PG/PC Interface" applet that the access point S7ONLINE is bound to IBHNet MPI. This binding is what the IBH driver and the S7 routing SDBs both look at.

3. S7 Routing Concept and Limitations

S7 routing is the transfer of online-services telegrams beyond the boundary of a single S7 subnet. A telegram is received on the engineering interface of the gateway CPU and re-emitted on a second interface; the CPU acts as a router. Routing is supported on the following SIMATIC CPUs as gateways:

• All S7-400 CPUs (PN/DP and DP variants)
• S7-300 CPUs with PN/DP or DP/DP interface and firmware that supports routing (for example CPU 319-3 PN/DP, CPU 315-2 PN/DP)
• ET 200S / ET 200pro IM with PN/DP interface and routing-capable firmware
• WinAC RTX and PC-based controllers

Per the Siemens functional manual on S7 routing, the gateway CPU must be configured as a routing node; this configuration is generated by NetPro or by the device configuration in TIA Portal and downloaded to the CPU as part of the System Data Blocks (SDB container, SDB 0 and SDB 999). If the SDBs are missing, the CPU can still execute the user program but the online-services layer has no routing table to consult.

Important constraints:

• Topology must be known to the project. The drive GSD files must be present in the STEP 7 hardware catalog. Without the GSD, the DP slave cannot be a destination of a route and STARTER/Scout will not enumerate the device under "Accessible Nodes".
• Accessible Nodes shows direct neighbors only. The PG/PC station on the MPI subnet sees the S7-400. Drives behind PROFIBUS are reachable only when STARTER/Scout is launched and a STARTER/Scout project is opened with the same topology and the same S7 routing path.
• Routing respects broadcast domains. A drive connected via a non-Siemens DP/DP coupler that does not pass S7 routing telegrams will be invisible.

4. STEP 7 Hardware Configuration

Build the project in the SIMATIC Manager with a PC station that represents the engineering workstation. The PC station is required even when the project is empty, because NetPro uses it to construct the routing SDBs.

1. Open SIMATIC Manager and create a new project.
2. Insert a SIMATIC 400 Station and assign the exact order number (MLFB) of the target CPU, for example 6ES7412-2EK06-0AB0 (CPU 412-2 PN) or 6ES7416-3ES06-0AB0 (CPU 416-3 PN/DP).
3. Insert a SIMATIC PC Station into the project.
4. Open HW Config on the PC Station and insert an IE General or CP 5611 / CP 5612 or, in the case of an IBH S7++ Link with MPI only, the Application station with the IBH S7 Softnet entry. For pure MPI routing the typical approach is the IE General placeholder bound to the IBH driver.
5. Open HW Config on the S7-400 Station. Add both interface subnets:
   • On port 1 (MPI/DP) set the interface mode to MPI, transmission rate 187.5 kbps, station address 2 (typical).
   • On port 2 (DP or PN) configure the PROFIBUS or PROFINET subnet and add the SINAMICS drives from the catalog using their GSD files.
6. For each drive, set the PROFIBUS address to match the hardware (typical values 4…15 for SINAMICS S120, 4…8 for G120).

5. PG/PC Station Assignment in NetPro

The PG/PC station in NetPro is what generates the routing SDBs that the gateway CPU needs. Without this step, "Accessible Nodes" will only ever list the S7-400 - never the drives.

1. Open NetPro on the PC station.
2. Right-click the PC station interface and choose Assign Interface if not already assigned.
3. Select the application IBHNet S7 (or IBH S7 Softnet) as the application on the interface.
4. Right-click the PC station interface and choose Assign Station to PG/PC. This is the critical step - it binds the PC station to the PG/PC role so that the S7 routing SDBs are built for the engineering role.
5. Verify that the PC station shows the same MPI subnet as the S7-400 and that the PC has a unique MPI address (default 0) on the same subnet.
6. Save and compile NetPro (Network → Save and Compile or F7).
7. Download the System Data to the S7-400. The download is a single action: PLC → Download to Target Station on the S7-400 CPU. The CPU must be in STOP or RUN-P, depending on what blocks are being downloaded.

After the SDBs are downloaded, the routing tables inside the S7-400 carry the following information:

• Engineering interface subnet (MPI)
• Destination interface subnet (PROFIBUS DP)
• Final-step DP slave address and slot

6. Installing SINAMICS Support Packages (SSP)

STARTER and Scout can only create online connections to drive objects whose device type is known to the engineering software. The device knowledge is delivered as Support Packages (SSP):

To install an SSP:

1. Download the matching SSP from the Siemens Industry Online Support portal product page for SINAMICS S120 / G120.
2. Close all running SIMATIC tools.
3. From the SIMATIC Manager main menu choose Options → Support Packages → Install.
4. Browse to the unpacked SSP folder and select the .spp file (for example SSP_SINAMICS_S120_V5_4_SP3_HeifPackage_2018xx.zip).
5. Restart STEP 7. The new SINAMICS device versions appear in the HW Config catalog and in the STARTER/Scout device catalog.

7. Going Online Through S7 Routing from STARTER/Scout

Once the SDBs are downloaded and the SSPs are installed, the S7 routing path is operational. Two methods are commonly used.

7.1 Method A - From the STEP 7 Hardware Project

1. Open the STEP 7 project containing the S7-400 and the configured drive objects.
2. Open HW Config and select the S7-400 CPU.
3. Press PLC → Online to establish the connection. The CPU must be reachable on the MPI subnet through the IBH adapter.
4. Right-click the drive in the project tree and choose Target Device → Online Access (or Download / Upload to Target Device in TIA Portal terminology). STARTER opens in a child window with the topology pre-filled from the STEP 7 project.
5. STARTER then performs a routing connection to the SINAMICS drive. Status messages show the gateway hops, for example IBHNet MPI → CPU412 port 1 (MPI) → CPU412 port 2 (DP) → S120 CU320 address 4.

7.2 Method B - From STARTER with Routing-Enabled Access Point

1. Open STARTER. Set the access point to S7ONLINE with target interface IBHNet MPI.
2. Open or create a STARTER project. Add the gateway CPU under Insert → SINAMICS_Integrated / S7 routing and enter the destination PROFIBUS address of the drive.
3. Set the access point of the device to DEVICE (ROUTING) and the device address to the destination DP address.
4. Press Connect to Target System (the plug icon). STARTER builds the routing SDBs on the fly and connects.

8. Uploading a Drive Without It Appearing in Accessible Nodes

Accessible Nodes on the MPI subnet will never list the SINAMICS drives; only the S7-400 is visible. To upload the drive to the PG, follow this sequence.

1. Open the STEP 7 project in the SIMATIC Manager.
2. Open HW Config on the S7-400 station. The drive slots must be present, and the drive GSD must be the same version family as the drive firmware on the cabinet (or the device type is Unknown, in which case install the matching SSP first).
3. Confirm the PG/PC station is online with the S7-400. The PG/PC must have a node address of its own on the MPI subnet (typically 0) and the SDBs must have been downloaded to the CPU in the previous step.
4. Right-click the drive object in the project and choose Target Device → Online → Upload to PG/PC. STARTER retrieves the drive parameters via S7 routing. If the drive is a SIMOTION D4x5, the upload may require the additional "target data" that was stored on the device at last download; without it, an upload is not possible.
5. For SIMOTION: ensure the engineering data is on the CF card. Otherwise, only the online snapshot of the device is available; an offline project is not produced.

9. Verification Checklist

Run the following checks before declaring the S7 routing path operational.

10. Diagnostic Buffer and Common Error Codes

The S7-400 diagnostic buffer reports routing problems in clear text. The most common events observed in this configuration:

11. Troubleshooting Matrix

12. Special Cases

12.1 S7-400 with Both MPI and PROFIBUS on the Same Physical Port

Some S7-400 CPUs have one combined MPI/DP port. Configure the port as MPI in HW Config; routing across the same physical port to a DP subnet is not possible. Use the second port for PROFIBUS. If the CPU has only one port, an external DP/DP coupler is required, but S7 routing does not pass through non-Siemens couplers in all firmware releases.

12.2 Mixing MPI at 19.2 kbps and PROFIBUS at 1.5 Mbps

Set the IBH S7++ Link to the same baud rate as the S7-400 MPI port. Mismatched rates produce intermittent timeouts. Use the IBHNet Configuration Tool to flash the adapter to 187.5 kbps for typical S7-400 MPI ports; some older plants run 19.2 kbps and require the adapter to be set accordingly.

12.3 Routing Through a CP 443-1 PN

When the S7-400 reaches PROFINET drives through a CP 443-1, the CP firmware must support routing. CP 443-1 EX30 and later support routing transparently. The PC station in NetPro must have an IE interface bound to the same PROFINET subnet; the SDBs are still produced by the S7-400, not by the CP.

12.4 S7 Routing Across PROFINET to G120 with PN Control Unit

For G120 with CU240E PN, the routing path is IBHNet MPI → CPU port 1 (MPI) → CPU port 2 (PN) → G120 PN. The S7-400 SDBs include the PROFINET name and IP of the G120. STARTER then connects across the PROFINET interface. The procedure is otherwise identical to the PROFIBUS case.

13. Reference Documentation

• SINAMICS S120 Support Packages - Siemens Industry Online Support
• S7 Routing Function Manual - Siemens TIA Portal documentation
• SIMATIC S7-400 Automation System, System Manual (entry ID 1117740)
• SINAMICS S120 Commissioning Manual (entry ID 109755352)