Configuring SINAMICS Telegram 999 for Free BICO Interconnection

Overview

SINAMICS S120 drive systems communicate with SIMATIC PLCs over PROFIBUS DP using either standard telegrams (1, 2, 3, 5, 6, 7, 9, 20, 81–86, 102–106, 110–118, 125, 136, 138, 139, 166, 220, 352, 370–395) or a freely-configurable telegram structure. Telegram 999 is the free-configuration option that lets the user map any BICO (Binector/Connector) source to any PZD (Process Data Word) and back. This article explains how to project Telegram 999 when integrating a SINAMICS CU310 DP (order number 6SL3040-0LA00-0AA1) with a SIMATIC S7-300 CPU 315-2DP using STEP 7 V5.4 + SP3 + HF1 (revision K5.4.3.1).

Telegram 999 is not exposed as a directly selectable entry inside the STEP 7 V5.4 hardware catalog. The hardware catalog tree SINAMICS S120 shows only standard telegrams up to telegram 392 under the CU310 DP node, while the SINAMICS S tree exposes a generic "Telegram Max: 16/16 PZD" entry. To enable Telegram 999, the SINAMICS S120 must be projected as a PROFIBUS DP slave in HWConfig with two universal (free) slots—one for process data inputs (I-addresses, drive→PLC) and one for process data outputs (Q-addresses, PLC→drive). The actual word counts and BICO mapping are then configured in the drive commissioning tool (STARTER for STEP 7 V5.4 projects, or Startdrive inside TIA Portal).

Prerequisites

• SIMATIC S7-300 CPU 315-2DP (6ES7315-2AG10-0AB0 or later) with integrated PROFIBUS DP master interface.
• SINAMICS S120 Control Unit CU310 DP, order number 6SL3040-0LA00-0AA1, firmware ≥ 4.3 (firmware 4.4, 4.5, 4.6, 4.7, 4.8 and 5.x also supported). Telegram 999 was introduced in early S120 firmware and is stable across all current releases.
• STEP 7 V5.4 + SP3 + HF1 (revision K5.4.3.1) with HWConfig tool.
• STARTER V4.x commissioning software with the SINAMICS S120 Support Package installed, or Drive ES Basic.
• PROFIBUS DP cable (6XV1830-0EH10 or equivalent), 9-pin D-sub connectors with terminating resistors enabled at both physical ends, baud rate ≤ 12 Mbit/s.
• GSD file SIEM81D8.GSD (or the device-specific GSD shipped with the firmware Support Package for the CU310 DP firmware version in use). Re-import the GSD after every firmware upgrade.

Understanding Telegram 999 and BICO

SINAMICS drives use BICO technology to route digital (Binector) and analog (Connector) signals between software function blocks. Every internal variable can act as a BICO source (signal provider) or BICO target (signal consumer). On the CU310 DP, BICO connectors interface with the PROFIBUS PZD layer through these drive parameters:

• r2050[0..15] — PZD receive word buffer (raw words arriving from the PLC over PROFIBUS IF1).
• p2051[0..15] — BICO source for each PZD send word on IF1 (drive→PLC).
• p0922 — IF1 PROFIBUS PZD telegram selection; set to 999 for free telegram.
• p2079 — IF1 PROFIBUS PZD send word count (drive→PLC).
• p2080 — IF1 PROFIBUS PZD receive word count (PLC→drive).
• p2081[0..15] / p2082[0..15] — Bit-level BICO routing for send words when the source is a Binector.
• p2099 — IF1 PROFIBUS connector source selector for receive word 0 (used implicitly by the BICO editor).

When Telegram 999 is active, the user defines:

1. Total number of PZD words sent to the PLC (Q-area, master receive).
2. Total number of PZD words received from the PLC (I-area, master send).
3. The BICO source connector feeding each send word via p2051[idx].
4. The BICO target connector driven by each receive word via the STARTER BICO editor (which internally links r2050[idx] to the chosen target).

Maximum configuration: 16 PZD words in each direction on IF1 of the CU310 DP. Words beyond the configured count are ignored and do not consume PROFIBUS bandwidth.

STEP 7 V5.4 HWConfig Configuration

Open SIMATIC Manager → PLC → Hardware to launch HWConfig. The PROFIBUS DP master system must first be configured on the CPU 315-2DP DP interface before the SINAMICS station is inserted.

Inserting the SINAMICS S120 DP Slave

1. In the hardware catalog (right pane), navigate to PROFIBUS DP → SINAMICS → SINAMICS S120 → CU310DP. The catalog order depends on the installed HSP; if the S120 tree is missing, install the SINAMICS S120 Support Package and restart HWConfig.
2. Drag the CU310DP entry to the PROFIBUS DP master system line on the station window.
3. Assign the PROFIBUS address to match the address switches on the CU310 DP (default: 3, valid range 1–126). The address can also be set in drive parameter p0918; whichever is higher priority by firmware version wins (firmware ≥ 4.5: p0918 takes priority when present).
4. Confirm with OK. The slave appears with default slots for standard telegram 1 in HWConfig.

Creating Input and Output Slots for Free Telegram

Telegram 999 is realized in HWConfig by deleting the default slot entries (typically configured for standard telegram 1) and inserting two universal (free) slots into the DP slave—one for input PZD (drive→PLC, occupies I-addresses) and one for output PZD (PLC→drive, occupies Q-addresses).

1. Open the DP slave properties dialog by double-clicking the CU310DP station.
2. Switch to the Slot Table tab. Existing default slots show standard telegram assignments inserted automatically.
3. Delete any default slot entries (right-click → Delete) that conflict with the free-telegram structure.
4. Click the first empty slot row and choose Insert → Universal Module. Configure this slot as the Input slot (drive→PLC). Set the Length to the number of send PZD words required (for example, 6 words = 12 bytes input).
5. Insert a second universal module at the next free slot row. Configure this as the Output slot (PLC→drive). Set the Length to the number of receive PZD words required (for example, 4 words = 8 bytes output).
6. Click the Addresses button on each universal slot to set the start I-address and start Q-address. STEP 7 proposes default addresses in the I/Q area of the CPU 315-2DP; record these values for use in the user program and the STARTER telegram configuration. The input slot consumes the I-address range; the output slot consumes the Q-address range.
7. Save and compile the HWConfig (Station → Save and Compile).

Addressing the I and Q Areas

For a CPU 315-2DP with default input/output area starting at IB 0 / QB 0, a typical Telegram 999 configuration reserves the following addresses:

In the STEP 7 user program, access these addresses with standard load/transfer operations, or via SFC14 (DPRD_DAT) and SFC15 (DPWR_DAT) for consistent data transfer (recommended when the telegram exceeds 4 bytes or when the data must be read/written atomically within one OB1 cycle).

STARTER Commissioning Tool Configuration

The Telegram 999 word counts and BICO mapping are configured in STARTER for STEP 7 V5.4 projects (or in Startdrive for TIA Portal projects).

Setting Telegram Type to 999

1. Open the STARTER project and connect to the CU310 DP online (PROFIBUS or the Ethernet service interface X127).
2. In the navigation tree, open Drive → Communication → PROFIBUS.
3. Set parameter p0922 = 999 (IF1 PROFIBUS PZD telegram selection = free telegram configuration).
4. Save the project and download to the drive (right-click the drive → Download to target device → RAM only, or RAM + ROM for retentive storage).

Configuring Send PZD Length and BICO Sources

Parameters controlling the PZD send word count and source routing (drive→PLC):

Open the STARTER Telegram Configuration editor (right-click the PROFIBUS interface → Telegram configuration). The editor shows the current p0922 selection, p2079 and p2080 lengths, and the source/target columns for each PZD word. Each row can be re-mapped by clicking the BICO selector in the source or target column.

Configuring Receive PZD Targets

Receive words (PLC→drive) are routed to BICO targets via the STARTER BICO editor. The PROFIBUS layer stores each received word in r2050[idx]; the BICO editor then connects r2050[idx] to the chosen target connector.

STEP 7 User Program Access

Use SFC14 (DPRD_DAT) for consistent read and SFC15 (DPWR_DAT) for consistent write to the CU310 DP. Example for a CPU 315-2DP with Telegram 999 occupying IW 0–IW 10 / QW 0–QW 6, base logical address 0:

// FB "CU310_T999" — Telegram 999 cyclic read/write
CALL SFC 14  // Read 12 bytes (6 PZD) from drive
  LADDR   := W#16#0      // Logical address base = 0
  RET_VAL := MW100       // Error code (0 = OK; W#16#80A1 = slave failure)
  RECORD  := P#DB99.DBX0.0 BYTE 12

CALL SFC 15  // Write 8 bytes (4 PZD) to drive
  LADDR   := W#16#0
  RECORD  := P#DB99.DBX12.0 BYTE 8
  RET_VAL := MW102

// Optional: extract status and control bitfields
      L   DB99.DBW 0        // Load status word 1 (ZSW1)
      T   MW 110            // Store for diagnostics
      L   DB99.DBW 12       // Load control word 1 (STW1)
      L   W#16#047E         // Pattern: pulse enable, no fault ack
      OW                      // OR with current control word
      T   DB99.DBW 12       // Write back

DB99 layout for Telegram 999 (offsets are byte offsets; words are 16-bit big-endian as PROFIBUS transmits them in motorola format):

PROFIBUS DP Performance Considerations

• Bus cycle time: The PROFIBUS DP cycle time on the CU310 DP equals the configured DP cycle time in HWConfig (Properties → DP master → Cycle). Typical values are 1–10 ms. Telegram 999 with up to 16+16 PZD adds ~32 bytes of process data which is well within the 12 Mbit/s PROFIBUS payload envelope (no impact on cycle time at standard baud rates).
• Application cycle: The drive-side application sampling of PZD occurs every p0115[0] basic sampling time. Mismatched application cycles between drive and PLC can be smoothed by averaging; no special configuration is required for Telegram 999.
• Watchdog: Configure the DP slave watchdog in HWConfig to ≥ 100 ms to avoid spurious bus timeouts during drive ramp-up or firmware boot. The default STEP 7 V5.4 watchdog of 10 ms is too short for cold starts.
• Consistency: SFC14/SFC15 read/write whole consistency regions atomically; using direct I/O access (L IW, T QW) on a Telegram 999 with more than 4 bytes may yield torn reads inside a single OB1 scan. Always use SFC14/SFC15 for telegram data, or pack the data into a process image partition updated via OB1.

Verification

1. Compile and download the STEP 7 hardware configuration (HWConfig → Station → Save and Compile → PLC → Download to Target Station).
2. Download the STARTER project to the CU310 DP (online → Download to target device → select target device by PROFIBUS address).
3. Power-cycle the drive and observe the CU310 DP LEDs: RDY (ready) green, BF (bus fault) off, DPRDY (PROFIBUS ready) green. If BF is solid red, the drive is not receiving a valid PROFIBUS frame; if BF blinks red, the drive is receiving frames but with a configuration mismatch.
4. Open the drive online diagnostics in STARTER (Drive → Commissioning → Control Panel) and confirm PROFIBUS communication is active. The status line shows "Cyclic PZD communication active".
5. Open the PROFIBUS diagnostics in STEP 7 (PLC → Module Information → Diagnostic Buffer) and confirm no "Distributed I/O: Station failure" or "Configuration error" entries.
6. In STEP 7, open a VAT or watch table on the I/Q addresses. Toggle the first control bit (OFF1, STW1.0) in the output control word and confirm the drive responds (status word bit "Operation enabled" r0052.2 sets, r0052.3 fault absence). Read the actual speed (IW 2) and verify it tracks the setpoint written to QW 0 within the configured ramp time.

Troubleshooting

Field Commissioning Tips

• Order matters: Always download the drive parameter set (STARTER) AFTER the HWConfig has been compiled and downloaded to the CPU. If you reverse the order, the PROFIBUS slave startup with the new telegram length will fail because the drive does not yet know about Telegram 999 (p0922 still equals the prior telegram number).
• GSD selection: For CU310 DP (6SL3040-0LA00-0AA1) use SIEM81D8.GSD or the device-specific GSD shipped with the firmware Support Package. Re-import the GSD after every firmware upgrade; older GSD revisions may not support Telegram 999 slot configurations correctly.
• Save and re-compile: Changing the slot length in HWConfig after Telegram 999 is in operation forces a STOP/START of the DP slave and briefly disconnects the drive. Plan length changes during commissioning or maintenance windows.
• Consistency: SFC14/SFC15 read/write whole consistency regions; using direct I/O access (L IW/QW) on a Telegram 999 with more than 4 bytes may yield torn reads. Always use SFC14/15 for telegram data.
• Diagnostic buffer: CPU diagnostic buffer entries "Distributed I/O: Station failure" or "Slave not found" usually indicate PROFIBUS address conflict. Verify the address set on the CU310 DP (p0918 or DIP switches) matches HWConfig. Address 0 is invalid on PROFIBUS DP.
• Double PLC project integration: When the STARTER project and STEP 7 project are integrated (Drive ES Basic routing), use "Load to PG" after HWConfig changes to refresh STARTER's view of the slave topology. Out-of-sync integration causes Telegram 999 to display the old length in STARTER even after HWConfig update.
• BICO consistency check: Before commissioning, run STARTER's online "BICO consistency" check (right-click drive → Properties → BICO check). It verifies that every receive-PZD BICO target is actually interconnected and that every send-PZD BICO source is valid.
• RAM only vs RAM + ROM: p0922 = 999 with custom p2051/p2080 mappings stored only in RAM is lost on power-cycle if the drive was downloaded "RAM only". Use "RAM + ROM" for production commissioning to persist the configuration.

Differences from TIA Portal / Startdrive

In TIA Portal V21 with the Startdrive option, Telegram 999 is selected as a typed TelegramType enum value in the device configuration view. The function returns the telegram type as a TelegramType enum, which can be assigned programmatically or selected from a dropdown. The HWConfig approach with two universal slots is replaced by a typed telegram structure inside the Startdrive device proxy; the slot table is hidden from the user and the telegram length is configured via the device properties. The underlying drive parameters (p0922, p2079, p2080, p2050/r2050, p2051) remain identical, so commissioning knowledge transfers directly between STEP 7 V5.4 and TIA Portal. See the TIA Portal V21 Startdrive Telegram function reference for the typed API and Startdrive integration details.

Standard Telegram Reference (For Comparison)

Hardware Compatibility

FAQ