Configuring New SINAMICS S120 Motor Modules with Legacy CU320

1. Overview and Compatibility Statement

SINAMICS S120 hardware generations are designed for forward and backward compatibility inside the same control-unit family. The original CU320 (type 1, MLFB 6SL3040-0MA00-0AA1) can, in the vast majority of cases, be paired with newer SINAMICS S120 Booksize motor modules, including the 6SL3120-2TE13-0AA4 double motor module, provided the firmware loaded on the CompactFlash card is recent enough to support the module's catalog variant. Newer motor modules are electrically and DRIVE-CLiQ compliant with the legacy CU320 — the modules will appear in the topology and can be commissioned. The trade-off is functional: features introduced in motor-module firmware that post-dates the CU320's CF card firmware version (in this case V2.6) cannot be activated. Safety functions, basic servo control, encoder evaluation and DRIVE-CLiQ diagnostics are not affected.

The same logic applies to the SIMOTION side. SIMOTION D445 (MLFB 6AU1445-0AA00-0CA0) operating with a SINAMICS integrated drive line is functionally aligned with the legacy CU320 firmware baseline, so a SIMOTION D445 running on the same V2.6 generation behaves identically to a CU320 with respect to module compatibility. The combination legacy CU320 + SIMOTION D445 + new SINAMICS S120 motor modules is therefore supported when firmware alignment is preserved.

2. Hardware Bill of Materials

The complete hardware list to be integrated, with Siemens MLFB / order numbers, is summarised in the table below.

3. Control Unit and Firmware Architecture

The legacy CU320 (type 1) is the first generation of the SINAMICS S120 central controller. It is identified by MLFB 6SL3040-0MA00-0AA1 and ships without on-board firmware — the firmware, parameter set and licenses are stored on a separate CompactFlash card inserted in the front of the unit. The card is a Siemens-proprietary CF card; standard consumer CF media are not accepted.

Relevant hardware characteristics of the CU320 (type 1):

• Six DRIVE-CLiQ ports (X100 through X105) on the front panel
• One PROFIBUS DP interface (X126) with PROFIdrive V3 profile support
• One RS232 commissioning interface
• Status LEDs (RDY, COM, OUT1, OUT2) and a 7-segment display for diagnostic codes
• Maximum of six controlled drive axes plus one line infeed
• 24 V DC logic supply via X124

The CompactFlash card 6SL3054-0CG01-1AA0 contains:

• CU320 firmware V2.6.x
• License certificate for "Performance Extension 1" (mandatory for 1FK7 high-inertia servomotors and for servo control with 1 ms current controller cycle)
• Parameter backup file (.../USER/SINAMICS/S120/PMEMORY.ACX)

Official documentation for the CU320 product is published on Siemens Industry Online Support (SIOS):
SINAMICS S120 CU320 product page

4. SIMOTION D445 Multi-Axes Bundle

The MLFB 6AU1445-0AA00-0CA0 is a pre-bundled D445 multi-axes configuration, comprising:

• One SIMOTION D445 module (6AU1445-0AA00-0AA0)
• One SIMOTION CF card with multi-axes package license M44 (6AU1400-2PA01-0AA0 -Z M44)

The D445 is a drive-based motion controller, meaning that one of the SINAMICS S120 axes is co-resident in the same hardware platform. The D445 contains an internal CU320-2-like drive controller; the external CU320 in the cabinet is a separate control unit that controls the additional SINAMICS S120 axes. PROFIBUS DP or PROFINET is used to cross-couple the two. From the user's perspective this is a classic "SIMOTION D + CU320" architecture.

Documentation for the D445 product is on SIOS:
SIMOTION D445 product page

5. 6SL3120-2TE13-0AA4 Double Motor Module

The MLFB 6SL3120-2TE13-0AA4 is a SINAMICS S120 Booksize Double Motor Module. Its role in the drive line is to provide two independent, axis-level inverters in one physical module. It is fed from a common DC link (the "booksize DC bus") produced by a line module (Active Line Module, Smart Line Module, Basic Line Module) elsewhere in the cabinet.

Front-panel interface layout:

• X1 / X2 — DRIVE-CLiQ to control unit and to the next module in the ring
• X21 / X22 — Motor power output (axis 1 and axis 2)
• X200 / X201 — 24 V control electronics supply (daisy-chained)
• DCPA / DCNA — DC-link bus bars (top side)
• PE bar — Protective earth

The "2TE13" segment of the MLFB decodes as:

• 2 – Double Motor Module (two drive axes)
• TE – Booksize form factor, internal air cooling
• 13 – Current class / size block. Cross-reference this against the SINAMICS S120 Catalog D31 to confirm the exact In rating for the user's revision of the card.

Product page on SIOS:
SINAMICS S120 Booksize motor module overview

6. 1FK7042 Servomotors

The two motors in this project — 1FK7042-2AF71-1BG2 and 1FK7042-2AF71-1CG2 — are members of the SIMOTION 1FK7 family, 63 mm frame, high-inertia (Compact / IN series) servomotors. The two MLFBs differ in the trailing designators; for 1FK7 this portion of the order number typically encodes the encoder option and shaft design. The B and C variants cover the two most common absolute encoder offerings (single-turn EnDat and multi-turn EnDat, respectively). Confirm the specific encoder/shaft configuration for the exact MLFB on the product page:
SIMOTION 1FK7 product page

General 1FK7042 family characteristics (verify for exact MLFB in SINAMICS S120 Configuration Manual / D31.1 catalog):

• Rated speed 3000 rpm (configurable up to 6000 rpm with field weakening)
• Static torque range 3.0 – 8.0 Nm (size dependent)
• Self-cooled (non-ventilated)
• Integrated multi-turn absolute encoder (EnDat protocol) – connector at the rear of the motor
• Plain shaft (no key) by default; balance grade Q

Use the SINAMICS S120 Configuration Manual (chapter on motor selection) to confirm the load data, thermal model and permissible S6 overload for the exact MLFB of the motor installed.

7. Cables and DRIVE-CLiQ Cabling

Three cable families are used in this project. The MLFBs follow Siemens' MOTION-CONNECT standard:

DRIVE-CLiQ is a real-time, point-to-point serial protocol. Topology rules:

1. No loops. Each DRIVE-CLiQ port has exactly one upstream neighbour and one downstream neighbour (or a terminating device).
2. No stars without a DMC20 / DME20 hub.
3. Maximum of 16 stations per line.
4. Maximum cable length between two DRIVE-CLiQ nodes: 70 m for MOTION-CONNECT 500, 100 m for MOTION-CONNECT 800PLUS.
5. Address is assigned automatically; do not use crossover cables (DRIVE-CLiQ cables are straight through, coded "blue" rings on both ends for motor-side, "blue/red" on the cabinet side).

8. SIMOTION SCOUT V4.4 Configuration Procedure

SCOUT V4.4 (Engineering Framework for SIMOTION) is the legacy configuration environment for the V2.6 firmware generation. It is installed on a Windows PC and connects to the SIMOTION D445 / CU320 line via PROFIBUS DP or Ethernet (STARTER/SCOOT routing). The new motor modules are configured from SCOUT in the same way as older ones.

8.1 Prerequisites

• SCOUT V4.4 SP1 or later installed, with HW-Update ≥ 4.4.0.10 applied (so the 1FK7042-2AF71-… MLFBs are present in the HW catalog)
• STARTER V4.4 (the integrated commissioning tool inside SCOUT) updated to at least V4.4.1.1
• The CF card 6SL3054-0CG01-1AA0 (V2.6) inserted in CU320 before commissioning
• CU320 online via Ethernet (recommended port: X120 service port) or PROFIBUS DP at 1.5 Mbaud
• 24 V DC logic power applied to all SINAMICS S120 components, line module pre-charged, motor modules in "Ready" state

8.2 Create the Project

1. Launch SCOUT V4.4. Select File → New Project. Choose a name and storage path with write access for non-administrator users (the default SCOUT path is C:\Siemens\SCOUT\S7PROJ).
2. Insert a new SIMOTION D445 device. In the navigator, right-click the project root → Insert SIMOTION device → D445. Confirm the MLFB 6AU1445-0AA00-0AA0.
3. Right-click the D445 and select Insert DRIVE-CLiQ hub / CU320. Point SCOUT to the external CU320 over PROFIBUS or Ethernet. The CU320's address must match its PROFIBUS rotary switch (factory default 6).
4. Right-click the CU320 and select Insert SINAMICS S120 drive line. SCOOT will read the topology once the line is online.

8.3 Configure the Double Motor Module

1. In the navigator expand the SINAMICS S120 drive line → Topology. The 6SL3120-2TE13-0AA4 should appear at the expected DRIVE-CLiQ port.
2. Right-click the double motor module → Properties. Confirm the order number 6SL3120-2TE13-0AA4; if SCOUT offers a later firmware, accept the existing V2.6 baseline so the module firmware matches the CF card.
3. Add the two 1FK7 servomotors. Use the SCOUT motor selection tool (D31.1) and pick the exact MLFBs 1FK7042-2AF71-1BG2 and 1FK7042-2AF71-1CG2 for the two axes. The encoder variant must match the physical hardware (B or C).
4. Configure the power stack data automatically. Open the drive → Commissioning → Automatic configuration. SCOUT will load the current controller, speed controller and encoder parameters from the motor's electronic nameplate.
5. Set the basic safety functions. If the application uses STO, configure Safe Torque Off via the integrated PROFIsafe channel on PROFIBUS DP or, more commonly, via the X130 / X131 terminals on the motor module. The V2.6 firmware supports SS1, STO, SLS, and SDI as of performance extension 1.

8.4 Axis Configuration

1. Insert two T0 axes (synchronous-axis objects) and link them to the two drives of the double motor module.
2. For each axis, set the mechanical system: p0100 = 1 (SI units), p0101 = 0 (synchronous servomotor), lead screw / load gear ratio, maximum velocity, maximum acceleration.
3. Configure the setpoint channel: PROFIdrive standard telegram 105 (servo) or 106 (servo with DSC) is typical. DSC requires the Performance Extension 1 license.
4. Build the project, save and download to the D445 and to the CU320. The download triggers a RAM → CF card write of all parameter changes.

9. Compatibility Limitations and Workarounds

Although the hardware is electrically and DRIVE-CLiQ compatible, the V2.6 firmware baseline imposes functional limits. The list below documents the categories of feature that may be missing in a V2.6 + 6SL3120-2TE13-0AA4 pairing. For each limitation, the engineering choice is either (a) live with the older function set, or (b) upgrade the CF card firmware to a V4.x / V5.x release (requires re-licensing for some Performance Extension features).

10. Verification and Commissioning Tests

Once the project is downloaded, perform the following verifications before releasing the machine to production.

1. Topology check. In SCOUT, open the SINAMICS S120 line → Topology → Online. All components (line module, double motor module, both SMCxx encoders if used) must be present and have green status.
2. Parameter consistency. Open Commissioning → Parameter check. Compare the loaded parameters against the project's offline copy. Differences of zero are expected on a clean first download.
3. Encoder check. With the motor de-energised, manually rotate the shaft and verify the position feedback increments correctly in Diagnostics → Setpoint / actual values. Verify the multi-turn EnDat counter persists after a power cycle.
4. Drive optimisation. Run the automatic controller optimisation (current controller, then speed controller). Save the parameters. The auto-tuning results are written to p0353 (current controller gain) and p1464 (speed controller gain).
5. Safety check. If STO is wired, force the STO input and confirm the drive shuts down with F01611 (or the relevant F-code for the safety configuration). Reset and confirm clean restart.
6. Reference run. Initiate a homing run on both axes. Verify the reference point repeatability is within the mechanically permitted tolerance.
7. MOVING test. Run a small jog routine (e.g. 90° step, 180° step) at 10% rated speed, then 50% rated speed. Listen for abnormal noise, check the motor current via Trace in SCOUT.
8. RAM → ROM. From SCOUT, copy RAM to ROM on the CU320 and on the D445. The parameters are now persistent.

11. Common Fault Codes for the Configuration

Refer to the SINAMICS S120/S150 List Manual for the complete fault list and remediation:
SINAMICS S120/S150 List Manual

12. Electrical and Mechanical Integration Notes

Beyond the SINAMICS-internal topology, the following cabinet-level requirements must be observed when integrating a legacy CU320 with newer motor modules:

• 24 V DC power supply. Provide a regulated 24 V DC source with sufficient current for all SINAMICS S120 components. The double motor module's electronics consume approximately 1.0 A per module at 24 V; the CU320 itself consumes approximately 1.5 A. Add 1.0 A for each SMCxx sensor module.
• Shield termination. Motor power cables (6FX5002-2DC10-1CF0) and signal cables must be shield-terminated at the entry plate of the cabinet. Use EMC-compliant cable glands (Pflitsch or equivalent) with 360° contact.
• PE routing. The protective earth of the motor must run back to the PE bar of the motor module, and the motor module's PE bar must be bonded to the cabinet PE at a single point.
• Cooling. The double motor module dissipates heat proportional to the load current. Mount in a vertical orientation in the cabinet; maintain at least 80 mm of clearance above and below for airflow.
• DC bus link. The 6SL3120-2TE13-0AA4 must be installed downstream of an SINAMICS S120 line module on the same DC bus. Verify that the line module is rated to supply the sum of the motor modules' peak currents plus the energy returned during braking.

13. Frequently Asked Questions