Simulating SINAMICS Control Unit Telegram 390 in SIMIT Simulation Platform

In Siemens SIMIT Simulation Platform, Telegram 390 is a specialized 2/2 PZD (Process Data) telegram designed exclusively for the SINAMICS Control Unit (such as CU320-2 or CU310-2), not for motor drive axes. It communicates Control Unit control/status words (CU_STW1, CU_ZSW1) and exchanges onboard digital I/O signals directly with the PLC. SIMIT includes native behavioral components for Telegram 390 in the SIMIT Drive Behavior Library. If the library is unavailable, engineers can model Telegram 390 using standard SIMIT bit/word conversion components or the Component Type Editor (CTE), mapping the two input and two output words directly to the virtual controller coupling image.

Executive Summary

During virtual commissioning of complex automation cells in SIMIT, simulation engineers frequently need to model multi-axis SINAMICS drive systems (such as SINAMICS S120). While individual motor axes utilize standard PROFIdrive telegrams (such as Telegram 1, 3, or 111), the centralized Control Unit (CU) object is often assigned Siemens Telegram 390 to allow the PLC to read onboard digital inputs and command auxiliary onboard relays. Engineers seeking Telegram 390 simulation blocks often struggle to locate or configure them in SIMIT. This guide explains the purpose of Telegram 390, details its PZD structure, and provides step-by-step instructions to model it in SIMIT.

Architecture and Fundamental Mechanics

The communication architecture of SINAMICS Telegram 390 separates Control Unit diagnostics from axis motion control:
1. Role of Telegram 390 in SINAMICS Architectures:
In multi-axis systems, the SINAMICS Control Unit (e.g., CU320-2) acts as the physical fieldbus node. While axes are Drive Objects (DO), the CU is its own independent Drive Object (DO 1). Assigning Telegram 390 to DO 1 allows the PLC to access the CU's physical onboard terminals (DI 0 to DI 7, DI/DO 8 to DI/DO 15) without needing separate distributed I/O slices.
2. Telegram 390 PZD Structure (2 Words In / 2 Words Out):
- Setpoint Direction (PLC $\rightarrow$ Drive, 2 PZD Words / 4 Bytes):
- Word 1 (CU_STW1): Control Word 1 for the Control Unit (Fault acknowledge, drive unit enable).
- Word 2 (CU_DO): Digital output commands driving onboard digital outputs of the CU.
- Actual Value Direction (Drive $\rightarrow$ PLC, 2 PZD Words / 4 Bytes):
- Word 1 (CU_ZSW1): Status Word 1 of the Control Unit (Ready to operate, fault present, warning present).
- Word 2 (CU_DI): Live states of physical digital inputs wired to the Control Unit terminals.
3. SIMIT Simulation Mechanics:
In SIMIT, the simulation coupling (via SIMIT Virtual Controller, PLCSIM Advanced, or PROFINET IO coupling) maps these 4 bytes into the I/O image. The SIMIT behavioral model takes virtual push-buttons or sensor signals, packs them into Word 2 (CU_DI), and sets Word 1 (CU_ZSW1 = 16#0003 - Ready) so the PLC perceives a healthy, responsive Control Unit.

Step-by-Step Implementation Procedure

Verify Telegram 390 Configuration in HW Config / TIA Portal:
a. Open the drive configuration in HW Config or Startdrive.
b. Select the SINAMICS Control Unit object (DO 1).
c. Confirm that telegram parameter p0922 = 390 is selected.
d. Note the peripheral input address (e.g., PIW 256, PIW 258) and output address (e.g., PQW 256, PQW 258).
Locate Native Telegram 390 Component in SIMIT:
a. Open your SIMIT simulation project.
b. In the right-hand task card, expand Components -> DRIVE or Drives Behavior Library.
c. Locate the component labeled Telegram 390 or CU_Telegram_390.
d. Drag and drop the component onto your simulation diagram sheet.
Construct Custom Telegram 390 Model (If Library Component is Unavailable):
a. If using SIMIT Standard without the specialized drives add-on, open the Standard Library -> Converters palette.
b. Insert a WordToBits block and a BitsToWord block.
c. For the Actual Value direction (to PLC):
- Wire a constant 16#0003 (representing Ready state CU_ZSW1) to the first input word.
- Connect virtual binary sensor signals to the bit inputs of BitsToWord to assemble the digital input word (CU_DI).
- Connect the two words to the coupling output signals mapped to PIW 256 and PIW 258.
  d. For the Setpoint direction (from PLC):
- Connect PQW 258 (CU_DO) to WordToBits to extract PLC digital output commands driving virtual actuators in SIMIT.
Establish Signal Coupling in SIMIT:
a. Open the SIMIT Coupling editor (e.g., Virtual Controller coupling).
b. Link the simulated telegram words to the corresponding PLC addresses imported from the hardware export.
c. Save the diagram and initialize simulation.

Verification

Start SIMIT simulation in RUN mode.
In the PLC engineering environment (STEP 7 / TIA Portal), monitor the input words for the Control Unit:
- Verify PIW 256 reads 16#0003 (Control Unit ready without faults).
Toggle a simulated digital input in SIMIT: confirm that the corresponding bit in PIW 258 transitions from 0 to 1 in the PLC monitoring table.
Write a bit to PQW 258 from the PLC: confirm the corresponding simulated actuator in SIMIT receives the digital command.

Limitations and Operational Precautions

Telegram 390 communicates only with the Control Unit; it cannot be used to control motor speeds, positions, or axis enables. Motor axis control requires assigning an axis telegram (e.g., Telegram 1 or 111) to the specific motor Drive Object.

Engineer FAQ

What is the difference between Telegram 1 and Telegram 390?

Telegram 1 controls a motor axis (speed setpoint and speed actual value), whereas Telegram 390 communicates Control Unit status and onboard digital I/O.