Interfacing Real SINAMICS Drive Data with SIMIT Simulation in SIMATIC PCS 7 Testing Environments

To read actual speed and encoder position data from a physical SINAMICS frequency converter located on a hardware test rack into a SIMIT simulation environment, engineers have two primary architectural approaches depending on whether the drive is communicating with an S7 controller. If the SINAMICS drive is connected to an S7-400 controller via PROFIBUS DP or PROFINET, SIMIT can read the actual drive telemetry directly from the controller's peripheral I/O image or instance data block using an S7-PLCSIM coupling, a Virtual Controller (VC) coupling, or a PRODAVE / S7-Communication coupling. If SIMIT must interface directly with the standalone drive without an intermediary PLC, data can be exchanged via OPC DA/UA or through an active fieldbus gateway using a SIMIT Unit.

Hardware-in-the-Loop vs Controller-in-the-Loop Architectures

In virtual commissioning and test-bench engineering, integrating physical field hardware (such as a SINAMICS S120 or G120 drive) with a SIMIT simulation model allows validation of kinematic calculations, material transport models, and safety interlocks.

Two primary testing paradigms exist:
1. Controller-in-the-Loop (CIL): The physical SINAMICS drive communicates cyclically with an S7-400 or CPU 410 controller across PROFIBUS/PROFINET using standard PROFIdrive telegrams (e.g., Telegram 1, 20, or 352). SIMIT couples to the controller (via S7-PLCSIM, SIMIT Virtual Controller, or PRODAVE) to monitor drive registers and simulate the mechanical load or upstream process.
2. Hardware-in-the-Loop (HIL): SIMIT acts as the virtual controller or virtual load, connecting directly to the physical drive's communication interface to read encoder pulses, speed feedback, and torque values in real time.

SIMIT Coupling Methods for SINAMICS Telemetry

Depending on hardware availability, SIMIT provides specific coupling interfaces:

S7 Communication (PRODAVE Coupling): Connects SIMIT across Industrial Ethernet directly to a physical S7-400 PLC. SIMIT reads variables from data blocks (DBs) where drive telegrams are unpacked by Drive ES or APL blocks (MotSpdCL).
S7-PLCSIM / Virtual Controller Coupling: Software-only simulation where the PCS 7 logic executes in PLCSIM and SIMIT simulates both the physical drive and process mechanics.
SIMIT Unit (Hardware Gateway): A dedicated hardware box connected to the physical PROFIBUS/PROFINET line, emulating the bus master and capturing drive telegrams at hardware cycle speeds (1-5 ms).
OPC DA / UA Coupling: SIMIT connects to a local or remote OPC server (such as SIMATIC NET OPC or STARTER OPC) to exchange drive parameters.

Step-by-Step Procedure: Configuring Controller DB Telemetry into SIMIT

Follow this procedure to extract SINAMICS speed data from an S7 controller into SIMIT using an S7 coupling:

Step 1: Identify Drive Telemetry Addresses in STEP 7

In HW Config, select the SINAMICS drive object on the PROFIBUS/PROFINET line.
Note the configured Telegram type (e.g., Standard Telegram 1: 2 words IN, 2 words OUT).
Identify the peripheral input address: e.g., PIW 512 (Status Word 1) and PIW 514 (Actual Speed NIST_A).
If using PCS 7 APL, open the CFC chart containing MotSpdCL. Check the input pin Rbk (Readback speed) or the block instance DB number (e.g., DB142).

Step 2: Configure Coupling in SIMIT

Open the simulation project in SIMIT.
In the navigation tree, double-click Couplings > New Coupling.
Select S7 Communication (or PLCSIM Advanced / S7-PLCSIM).
In the coupling properties, configure connection parameters:
- IP Address of the physical CPU or local loopback.
- Rack: 0, Slot: 3 (for S7-410).
Switch to the Signals tab and click Import Signals or manually add a signal:
- Name: Actual_Drive_Speed
- Data Type: INT (or REAL)
- Address: PIW514 or DB142.DBD16
Apply a scaling formula in SIMIT to convert raw hexadecimal speed ($16#4000 = 16384 = 100\%$) into physical RPM:
$$RPM = \frac{\text{RawValue}}{16384.0} \times \text{RatedSpeed}$$

Step 3: Connect Telemetry to Simulation Components

Drag the Actual_Drive_Speed signal from the Signals task card onto the SIMIT simulation diagram.
Connect it to visualization displays, digital charts, or downstream mechanical model components.
Start SIMIT simulation mode. Accelerate the physical drive on the test bench and verify that the SIMIT speed indicator tracks the physical drive tachometer in real time.

Comparative Coupling Matrix for Drive Simulation

The table below outlines available coupling mechanisms for interfacing SINAMICS drive data into SIMIT:

Coupling MechanismRequired HardwareCommunication ProtocolUpdate CycleTypical ApplicationS7-PLCSIM / Virtual ControllerPC only (No extra HW)Internal Shared Memory10 ms - 100 msSoftware testing of PCS 7 control logicPRODAVE (S7 Communication)Physical S7-400 PLC + PC NICS7 Protocol (ISO-on-TCP)20 ms - 50 msHybrid test rack with real PLC and real driveSIMIT Unit (Hardware)SIMIT Unit PN/DP moduleReal Fieldbus (PN/DP)1 ms - 5 msHigh-speed Hardware-in-the-Loop drive testingOPC DA / UA CouplingPC with OPC ServerOPC UA over TCP50 ms - 200 msConnecting third-party drive software or SCADA

Verification

To confirm that real SINAMICS drive data is streaming accurately into SIMIT:
1. Signal Value Inspection: In SIMIT, open the Signal Table and monitor Actual_Drive_Speed.
2. Drive Ramp Test: Using the physical drive operator panel (BOP/AOP) or STARTER control panel, ramp the motor from 0 to 1500 RPM.
3. Linearity Audit: Verify that the SIMIT signal smoothly scales from 0 to 1500 RPM in exact alignment with the physical shaft tachometer.
4. Trip State Verification: Trigger an intentional fault on the SINAMICS drive (e.g., Safe Torque Off - STO); verify that SIMIT immediately reflects status bit changes in Status Word 1.

Limitations and Operational Precautions

Observe the following virtual commissioning constraints:
- PRODAVE couplings poll PLC data asynchronously; do not rely on PRODAVE for sub-millisecond dynamic torque calculations or high-speed motion synchronization.
- SIMIT cannot physically back-drive a motor; simulated mechanical loads must be fed into the drive control loops as electrical torque-limit setpoints.
- Always validate final license quantities and MLFBs against the applicable Siemens catalog and authorized distributor quotation when purchasing SIMIT simulation components.

Engineer FAQ

How does SINAMICS represent 100% nominal speed in PROFIdrive telegrams?

In standard PROFIdrive telegrams (such as Telegram 1 or 352), speed is represented as a normalized 16-bit integer where 100% rated speed equals 16#4000 (16,384 decimal). A value of 16#7FFF (32,767) corresponds to nearly 200% speed.

Can SIMIT simulate the load torque back to the physical SINAMICS drive?

Yes, but simulating load torque back into a physical drive requires either a regenerative test motor mechanically coupled to the drive shaft, or injecting a simulated torque-limit signal into the drive's analog input / fieldbus control telegram.

Do I need a separate SIMIT license to use the PRODAVE coupling?

The standard SIMIT engineering license includes basic couplings (such as S7-PLCSIM, Virtual Controller, and S7 Communication / PRODAVE). Advanced high-speed Hardware-in-the-Loop testing with SIMIT Unit requires the SIMIT Unit hardware and associated firmware license.