Configuring SIMOTION D410-2 PROFINET IRT Sync with CU320-2 PN

Overview

SIMOTION D410-2 motion controllers and SINAMICS S120 CU320-2 PN drive controllers are designed to operate as a tightly-coupled isochronous system over PROFINET IRT. When migrating a flying-saw or similar high-dynamic application from a SIMOTION D410-2 with PM340 power module to a D410-2 plus S120 Smart Line Module / Motor Module configuration, engineers frequently encounter PROFINET consistency-check errors that block project download and prevent synchronous operation. The most common failure mode involves message frame 10 in slot 1 of the CU320-2 PN and the isochronous-mode sub-module in slot 1.2, both of which require IRT High Performance and Dynamic Servo Control (DSC) to be fully wired into the HW Config of both devices.

This reference walks through the root cause of the consistency-check errors, the exact HW Config changes required on the CU320-2 PN PROFINET interface, the topology editor settings that must match the physical cabling, and the verification steps to confirm isochronous operation before bringing the axis online. The procedure described here aligns with the SIMOTION D410-2 Commissioning Manual and the TIA Portal / SCOUT configuration guide for SIMOTION controller with PROFINET IO drive.

System Architecture: D410-2 and CU320-2 PN over PROFINET IRT

The SIMOTION D410-2 (order number family 6AU1410-2xxxx) integrates the SIMOTION runtime, an isochronous PROFINET IO controller, and two PROFINET ports on the front-panel connector X150 (P1 and P2). The SINAMICS S120 CU320-2 PN (order number 6SL3040-1MA01-0AA0) provides a separate PROFINET interface with two additional ports. In a flying-saw migration, the D410-2 acts as the sync master and the CU320-2 PN as the sync slave, while the SINAMICS S120 Smart Line Module (e.g. 6SL3130-6AE15-0AB1) handles the DC bus and a Single Motor Module (e.g. 6SL3120-1TE13-0AA4) drives the saw servo.

The isochronous PROFINET path is what enables the SIMOTION position controller to read actual values and write setpoints to the drive within the same bus cycle, with deterministic jitter typically below 1 µs. This is essential for any application with torque or velocity loops closed across the bus, including flying-saw registration control.

Problem Description: Consistency Check Failures

When the SIMOTION D410-2 is configured as an IRT High Performance sync master and the S120 with CU320-2 PN is configured as an IRT High Performance sync slave, the SIMOTION SCOUT / TIA Portal consistency check generates the following errors before allowing download to the controller:

With device "S120xCU320x2xPN", module "SIEMENS message frame 10" in slot "1"
must be operated isochronously either in the "IRT high performance" RT class,
or it must be replaced by a module without DSC.

On device "S120xCU320x2xPN", (sub)-module in slot = 1.2
should be operated in isochronous mode.

Both messages point to the same root cause: the message frame 10 (also referenced as SIEMENS telegram 10 / PROFIdrive telegram 10) on the CU320-2 PN requires DSC, and DSC requires the sub-slot to be in isochronous mode. If the IO device settings of the CU320-2 PN do not declare the slot 1.2 sub-module as isochronous, the consistency check blocks the project. The errors are typically accompanied by a project tree warning stating "no connection between SyncMaster and SyncSlave" because the sync relationship cannot be resolved until the isochronous assignment is correct.

Root Cause Analysis

PROFINET IRT distinguishes between three RT classes:

• RT (Real-Time): Non-isochronous, no deterministic latency.
• IRT (Isochronous Real-Time): Reserved time-slice for isochronous traffic, configurable bandwidth.
• IRT High Performance: Tightest synchronization with sub-millisecond jitter and DSC support.

Dynamic Servo Control (DSC) is a Siemens-specific extension on top of IRT High Performance. With DSC, the position controller runs inside the drive rather than in the SIMOTION controller, and only the position actual value / setpoint is transmitted on PROFINET. This dramatically reduces bus load and is required for cycle times below 1 ms on a single axis.

When you drop a CU320-2 PN into the HW Config and select Siemens message frame 10 (the default for high-performance SIMOTION-to-SINAMICS links), the IO controller implicitly assumes DSC. DSC in turn requires:

1. The drive sub-slot to be assigned to an isochronous PROFINET task (Ti).
2. The drive to be configured as a sync slave in the IRT domain.
3. The send cycle clock of the sync master to be less than or equal to the supported DSC cycle of the drive.

If the IO-cycle assignment on the CU320-2 PN PROFINET interface is left at the default (or set to "free running"), the consistency check produces the two errors shown above. The fix is to explicitly assign the interface to the SERVO task on the controller side and to declare slot 1.2 isochronous on the drive side.

Prerequisites

Before applying the fix, verify the following:

• SIMOTION SCOUT (V4.5 / V5.x) or TIA Portal with SCOUT TIA add-on is installed and licensed.
• SINAMICS S120 support package (SSP) for CU320-2 PN is installed (minimum SSP V4.x or V5.x to match the D410-2 firmware).
• SIMOTION D410-2 firmware and SINAMICS CU320-2 PN firmware are compatible. Refer to the SIMOTION D410-2 commissioning manual for the supported combination matrix.
• The PROFINET cable between D410-2 port P2 and CU320-2 PN port P1 is installed and labeled; both ports are at 100 Mbps full-duplex autonegotiated.
• You have the HW Config of the existing D410-2 project open, with the new CU320-2 PN already inserted as a PROFINET IO device.

Resolution Procedure: HW Config IO Cycle SERVO Setting

1. Open the D410-2 project in SCOUT or TIA Portal. Navigate to the project tree, expand the SIMOTION D410-2 station, and double-click the device icon to open HW Config.
2. Open the PROFINET interface of the CU320-2 PN. In the HW Config station window, double-click the X150 PN interface on the CU320-2 PN (not on the D410-2). The Properties dialog of the PROFINET IO device opens.
3. Switch to the IO Cycle tab. The IO Cycle tab lists the PROFINET task system and the assignment of each IO device / sub-module to a time slice.
4. Set SERVO in the list field at the bottom of the dialog. Click the list field on the row corresponding to slot 1 (the CU320-2 PN control unit itself) and slot 1.2 (the sub-module hosting the message frame 10 / DSC channel). Select SERVO from the drop-down list. This binds the drive's PROFINET cycle to the SIMOTION Servo task (typically 1 ms for flying-saw applications; can be 500 µs or 250 µs if the D410-2 and CU320-2 both support the lower cycle).
5. Confirm IRT High Performance is selected for the X150 PN interface. In the Properties > General tab of the CU320-2 PN X150 interface, ensure IRT mode is set to High Performance and Synchronization role is set to Sync Slave.
6. Confirm the D410-2 X150 PN interface. On the SIMOTION D410-2 side, the X150 PN interface must be set to IRT, High Performance, and Sync Master. The send cycle clock must match the SERVO task that the drive was assigned to (e.g. 1.000 ms).
7. Save and re-run the consistency check. Press Ctrl+S in HW Config, then in SCOUT choose Project > Check consistency. The two errors regarding message frame 10 and slot 1.2 isochronous mode should disappear.
8. Re-open the project from scratch if errors persist. A frequent secondary cause is residual settings from a previous migration. If the consistency check still fails after step 7, create a brand-new SIMOTION project, re-insert the D410-2 and CU320-2 PN, redo the configuration from a blank state, and re-transfer to the controllers. Do not start from the old D410-2 / PM340 project.

PROFINET IRT Topology Configuration

The PROFINET topology editor in HW Config enforces that the logical port interconnection matches the physical cabling. For IRT High Performance this is mandatory, not optional.

1. Right-click the PROFINET IO system and choose PROFINET IO Topology.
2. Drag a connection from D410-2 port X150 P2 to CU320-2 PN port X150 P1.
3. Set the cable length to a value less than 20 m for typical cabinet installation; the editor will round up to the nearest supported length tier (max 100 m, but isochronous jitter budget tightens with length).
4. Verify the sync domain contains only the D410-2 (master) and CU320-2 PN (slave). Additional switches in the path must support IRT (e.g. SCALANCE XC-200 or XR-500 series).

If the topology editor rejects the connection or the consistency check reports a topology mismatch, double-check the wiring diagram: PROFINET port LEDs on both devices should be solid green when the link is up. The SIMOTION D410-2 LED diagnostics reference lists the LED states for PROFINET synchronization, including the green steady / green flashing pattern that indicates the PN interface is synchronized to the send cycle clock of PROFINET IO with IRT and is forwarding IRT data.

Flying Saw Migration: PM340 to S120 Smart Line Module

The PM340 power module is a single-axis compact block with a built-in rectifier and limited braking capability. In flying-saw applications the deceleration energy from a rapid stop or emergency stop frequently exceeds the PM340's internal brake chopper / resistor rating, causing either F30002 DC-link overvoltage faults or thermal overload on the brake resistor.

Migrating to S120 with a Smart Line Module (SLM) or Active Line Module (ALM) decouples the line-side rectification from the axis module. The SLM (6SL3130-6AE15-0AB1, 5 kW / 10 kW / 16 kW variants) supplies unregulated DC bus voltage and can absorb regenerative energy through the line filter or feed it back to the line if an Active Line Module is used. The axis amplifier becomes a separate Single Motor Module (6SL3120-1TE13-0AA4 for 3 A / 6SL3120-1TE15-0AA4 for 5 A, etc.).

Key sizing checks during migration:

For three-phase sizing of the new S120 line infeed, use kVA = sqrt(3) * V_LL * I_line / 1000 with V_LL = 400 V (Europe) or 480 V (US) and I_line measured per-phase from the existing PM340 input. If the existing PM340 is sized for single-phase 230 V operation, the single-phase formula kVA = V * I / 1000 applies instead. Always confirm the topology from the original wiring diagram before sizing the SLM.

Verification and Diagnostics

After the consistency check passes and the project has been downloaded, verify isochronous operation on the running system:

1. Check PROFINET LEDs on the D410-2. Both port LEDs should be solid green. The Sync LED (where present) should be solid green, indicating the controller has entered the IRT sync domain as sync master.
2. Check PROFINET LEDs on the CU320-2 PN. Both port LEDs should be solid green, and the Sync LED should be solid green, indicating the drive is following the master clock as sync slave.
3. Use the SIMOTION diagnostics buffer. Open SCOUT, connect online, and inspect Diagnostics > Motion Buffer. There should be no entries of class 4 (synchronization error) on startup.
4. Use SINAMICS STARTER / Startdrive. Connect online to the CU320-2 PN and check parameter r2043 (PROFINET interface diagnostics), which contains the current IRT state and cycle-time jitter. Values below 1 µs of jitter confirm proper isochronous operation.
5. Enable the axis in SIMOTION SCOUT. Open the axis diagnostics, navigate to the following-error trace, and command a small jog. The following error should settle to zero within one Servo cycle, confirming DSC is active.

Troubleshooting Matrix

Best Practices and Field-Proven Caveats

• Always start from a blank SIMOTION project when migrating between drive platforms. Carry-over settings from PM340 configurations frequently carry incompatible telegram and DSC flags.
• Reserve the fastest PROFINET send cycle clock only if both the D410-2 and the CU320-2 PN explicitly support it. The SIMOTION D410-2 commissioning manual lists the minimum and maximum supported cycle times per firmware version.
• Keep PROFINET cable length as short as practical in the cabinet. The 20 m guideline mentioned in the consistency check ensures deterministic jitter under typical cabinet installations.
• When using DSC, the position controller is in the drive. Any change to DSC parameters (e.g. message frame type) on the drive side must be mirrored on the SIMOTION axis configuration; otherwise the controller will interpret position setpoints incorrectly.
• Document the PROFINET topology in the project notes so that maintenance technicians can re-create it if the project archive is lost.

Frequently Asked Questions