Configuring Siemens G120X Profinet Free Telegram in TIA V16

Overview

The SINAMICS G120X is a Siemens frequency inverter designed for pumps, fans, and compressors in infrastructure applications: water and wastewater, HVAC, building automation, and district heating. It is the successor to the G120P family and covers the 0.75 kW to 630 kW power range with 3-phase 400 V or 3-phase 690 V class supplies. The drive supports PROFINET, PROFIBUS DP, Modbus TCP, and EtherNet/IP on its CU230P-2 control units and is engineered exclusively for SINAMICS Startdrive (the integrated TIA Portal configuration tool). The legacy STARTER commissioning software does not support the G120X and cannot connect to it over USB or PROFINET.

The drive exposes its process data through PROFIdrive telegrams. Siemens supplies a list of standard telegrams (1, 2, 3, 5, 6, 7, 9, 20, 35, 110, 111, 220, 352) for common applications. When none of these match — for example, when a pump skid needs eight process variables in addition to control word, setpoint, status, and actual — a free telegram (also called free PZD configuration, telegram 999, or in some firmware versions telegram 396) is selected. The free telegram can hold up to 16 PZD words in each direction; this article documents a verified working configuration of 12 words out / 12 words in on a S7-1515-2 PN with TIA Portal V16 and Startdrive V16.

The working installation pattern is to split the telegram into individual WORDs on the PLC side and address each word through PN peripheral IO (PEW / PAW / %IW / %QW), then scale the integer values into REAL engineering units. SINAMICS Startdrive does not provide pre-built symbolic tags for a free telegram the way it does for standard telegram 1, so the user is responsible for defining the data block, mapping the IO addresses, and implementing the STW1/ZSW1 bit handling. The drive commissioning itself is performed through SINAMICS Startdrive or through the on-board Web Server (via IOP-2 or Smart Access Module, since Starter is not supported).

Document scope:

• Hardware and software prerequisites for G120X PROFINET integration with TIA Portal V16
• Free telegram 12/12 layout (control word, setpoint, status, actuals, process data)
• PROFIdrive STW1 / ZSW1 bit definitions used in PZD1 of the free telegram
• PLC program pattern: WORD split on the S7-1500 side, symbolic DB mapping, scaling formulas
• IOP-2 / Smart Access Module Web Server parameter access (replacement for Starter)
• Commissioning checklist, fault diagnosis matrix, and migration notes from V17

Prerequisites

PROFINET Network Configuration

Before configuring the telegram, the PROFINET side must be in order. On the S7-1515-2 PN side, assign an IP address and a PROFINET device name to the controller interface (Properties → Ethernet addresses → IP protocol → set IPv4 address; Properties → PROFINET interface → PROFINET device name). On the G120X side, the IP address and PROFINET device name are stored in the CU230P-2 control unit non-volatile memory and are set by either:

• TIA Portal during device configuration (transferred with the "Assign PROFINET device name" action), or
• Web Server (SAM) → Settings → PROFINET, or
• IOP-2 → Commissioning → Network.

The PROFINET device name is case-sensitive and must match exactly between controller and device. A mismatch triggers fault F08501 (PROFINET configuration fault) on the drive and a "station failure" diagnostic on the PLC.

Configuring the Free Telegram

The free telegram is configured in two locations: the inverter parameter set (which defines the contents of each PZD word) and the TIA Portal device configuration (which defines the IO addresses of those PZD words). The two must match exactly, otherwise the drive raises F01910 (PROFINET telegram failure) on power-up.

For the general procedure to select and configure a telegram in TIA Portal, see the official documentation: Siemens TIA Portal communication telegrams configuration. The free telegram (telegram 999) is selected from the same drop-down list as the standard telegrams; once selected, the length is chosen (e.g., 12 / 12) and TIA Portal reserves IO addresses accordingly.

Inverter-side PZD configuration

Parameters p0922 and p2051/p2061 define the PZD layout. For a free telegram, set:

p0922  = 999         ; free telegram configuration (or 396 on newer firmware)
p2051[0]  = 47       ; STW1  (control word 1)        into PZD1 out
p2051[1]  = 167      ; NSOLL_A (speed setpoint)     into PZD2 out
p2051[2]  = 0        ; user-defined PZD3 out
p2051[3]  = 0
...
p2051[11] = 0        ; 12th output word
p2061[0]  = 52       ; ZSW1  (status word 1)        from PZD1 in
p2061[1]  = 61       ; NIST_A (speed actual)        from PZD2 in
p2061[2]  = 27       ; IAIST  (current actual)      from PZD3 in
p2061[3]  = 28       ; PIST   (active power)        from PZD4 in
...
p2061[11] = 0        ; 12th input word
p0971 = 1            ; copy RAM to ROM and activate

The exact list of available connector (r-parameters) and binector (b-parameters) is in the SINAMICS G120X Parameter List (function diagrams 2440 and 2450). Connector r755, for example, is the "supplementary setpoint" and can be used for a secondary control variable such as pressure or flow in a pump application.

TIA Portal device configuration

Open Devices & Networks, drag the G120X from the catalog (Hardware catalog → Drives → SINAMICS → SINAMICS G120X) into the PROFINET subnet of the S7-1500, and double-click the device. Under PROFINET interface → Telegram configuration, insert a free telegram with length 12 / 12. If the dialog only allows standard telegrams, the Startdrive HSP has not been installed; install the HSP first and reload the catalog.

The TIA Portal IO addresses start at the next free input/output word in the CPU process image. Typical allocation with a S7-1515-2 PN and no other PN drives:

• Inputs IW 100..111 (12 words) → PZD1..PZD12 from drive to PLC
• Outputs QW 100..111 (12 words) → PZD1..PZD12 from PLC to drive

Splitting the Telegram into WORDs on the S7-1500

Unlike standard PROFIdrive telegrams (where SINAMICS Startdrive provides pre-built DBs with descriptive tags such as Drive.ActualSpeed or Drive.SetpointSpeed), a free telegram exposes only raw PZD words. The PLC program must unpack every word and the integrator must define the symbolic layout.

Symbolic IO mapping (recommended)

Define a global DB of type STRUCT for the 12 input and 12 output words, or expose the PN IO addresses as structured tags in the PLC tag table. The cleanest pattern uses a data block DB_DriveFreeTlg with non-optimized access (so that the peripheral IO can be mapped to it directly via absolute addressing):

DATA_BLOCK "DB_DriveFreeTlg"
{ S7_Optimized_Access := 'FALSE' }
VERSION : 0.1
NON_RETAIN
  STRUCT
    STW1         : WORD;      // PZD1 out - control word 1 (PROFIdrive)
    NSOLL_A      : INT;       // PZD2 out - speed setpoint (4000h = 100% p2000)
    UserPzd3Out  : WORD;      // PZD3 out
    UserPzd4Out  : WORD;      // PZD4 out
    ...
    UserPzd12Out : WORD;      // PZD12 out
    ZSW1         : WORD;      // PZD1 in - status word 1 (PROFIdrive)
    NIST_A       : INT;       // PZD2 in - speed actual
    IAIST        : INT;       // PZD3 in - current actual (smoothed)
    PIST         : INT;       // PZD4 in - active power
    MIST         : INT;       // PZD5 in - torque actual
    ...
    UserPzd12In  : WORD;      // PZD12 in
  END_STRUCT;
END_DATA_BLOCK

In the PLC tag table, map the PN IO addresses directly onto this DB: input %IW100 → DB_DriveFreeTlg.ZSW1, input %IW102 → DB_DriveFreeTlg.NIST_A, etc. For S7-1500 optimized blocks, create separate INPUT / OUTPUT tags of type WORD with the PN addresses and copy them inside OB1 into the structured DB.

SCL example (OB1)

// PLC -> Drive (12 words out)
"DB_DriveFreeTlg".STW1         := %QW100;
"DB_DriveFreeTlg".NSOLL_A      := %QW102;
"DB_DriveFreeTlg".UserPzd3Out  := %QW104;
... (continue for all 12 output words)

// Drive -> PLC (12 words in)
"DB_DriveFreeTlg".ZSW1         := %IW100;
"DB_DriveFreeTlg".NIST_A       := %IW102;
"DB_DriveFreeTlg".IAIST        := %IW104;
"DB_DriveFreeTlg".PIST         := %IW106;
"DB_DriveFreeTlg".MIST         := %IW108;
... (continue for all 12 input words)

This is the "split telegram into WORDs" technique the verified V16 installation uses. The PLC tags table provides the symbolic mapping, and the OB just copies 12 words each direction. From this point on, the rest of the program accesses the DB symbolically (DB_DriveFreeTlg.STW1, DB_DriveFreeTlg.NIST_A) and never touches the peripheral IO directly.

PROFIdrive STW1 (Control Word 1) Bit Map

The control word is always bit-coded per the PROFIdrive profile (PNO order No. 3.172). Bit numbering in the S7 is 0-based (LSB = bit 0). The drive's behavior depends on the active control source; for this telegram, p0852[0] = 0 (PROFINET is the active control source).

Typical run command sequence — set bits in this order with at least one PLC cycle between each step:

// Pre-ON state (drive ready, line contactor open)
STW1 := 16#047E;   // 0000 0100 0111 1110b
// = bit 6 (enable setpoint), bit 5 (unfreeze), bit 4 (ramp enable),
//   bit 3 (enable op), bit 2 (OFF3 cleared), bit 1 (OFF2 cleared), bit 0 (OFF1 = 0)

// ON command (drive ramps to NSOLL_A)
STW1 := 16#047F;   // add bit 0 (ON/OFF1 = 1)

Stop sequence: drop bit 0 → drive ramps to 0 with p1121 OFF1 ramp; drop bits 0, 1, 2 → OFF2 coast stop; drop bits 0, 1, 2 with bit 2 already 0 → OFF3 fast stop.

PROFIdrive ZSW1 (Status Word 1) Bit Map

The PLC must supervise bit 9 (Control requested) before sending any motion command. If bit 9 is 0, the drive is in local control (IOP-2, SAM, terminals) and ignores STW1. The handshake is:

• Set STW1 bit 10 = 1 → request control
• Wait for ZSW1 bit 9 = 1 → confirmed
• Then issue ON/OFF1 in bit 0

Recommended 12/12 PZD Layout for Pumps and Fans

The most common 12/12 free telegram layout for pump and fan applications reserves PZD1 and PZD2 for the mandatory PROFIdrive STW1/ZSW1 and NSOLL_A/NIST_A pair. PZD3..PZD12 are user-defined:

The scaling reference parameters p2000 (reference speed), p2002 (reference current), and p2003 (reference torque/power) must be set to match the application motor nameplate before NSOLL_A / NIST_A / IAIST / PIST / MIST values have any physical meaning. Siemens default values are 1500 rpm / 100% / 100%; these must be re-entered to match the actual motor.

Scaling and Engineering Units

All PROFIdrive setpoints and actuals are normalized to 4000h (16384 decimal) = 100% of the reference value. To convert to engineering units in the PLC:

// Speed setpoint (NSOLL_A, INT) -> REAL in rpm
n_set_rpm := (INT_TO_REAL("DB_DriveFreeTlg".NSOLL_A) / 16384.0) * "Config".p2000;

// Speed actual (NIST_A, INT) -> REAL in rpm
n_act_rpm := (INT_TO_REAL("DB_DriveFreeTlg".NIST_A) / 16384.0) * "Config".p2000;

// Current actual (IAIST, INT) -> REAL in amperes
i_act_A := (INT_TO_REAL("DB_DriveFreeTlg".IAIST) / 16384.0) * "Config".p2002;

// Power actual (PIST, INT) -> REAL in kW
p_act_kW := (INT_TO_REAL("DB_DriveFreeTlg".PIST) / 16384.0) * "Config".p2003;

The negative range is supported for setpoints with reversal (NSOLL_A = 0xC000 = -16384 = -100%). The S7-1500 INT data type is signed 16-bit and handles this natively; do not convert NSOLL_A to WORD in the DB if you intend to use the signed interpretation.

Web Server as a Replacement for Starter

Because Starter is not supported on the G120X, all parameter editing is done either through SINAMICS Startdrive (inside TIA Portal, online), through an IOP-2 plugged into the control unit, or through the on-board Web Server. The Web Server is enabled by inserting either the IOP-2 or the Smart Access Module (SAM) into the front of the CU230P-2 control unit. Once inserted, the SAM creates a Wi-Fi access point (SSID SAM_<serial>); connecting a laptop or tablet to that SSID exposes the drive's diagnostics and parameter list at the URL printed on the SAM label (typically 192.168.1.1).

The Web Server can:

• Show and acknowledge faults (the "Diagnostics" page mirrors r0947 / r2124)
• Read and write all parameters (the "Parameter list" page allows p0922, p2051, p2061 to be set)
• Perform a guided first commissioning (matches the TIA Portal Startdrive wizard)
• Update firmware via the Web Server interface
• Save and restore parameter backups (RAM → ROM, RAM → SD card, SAM → file)

Commissioning Procedure

1. Wire the G120X according to the wiring diagram in the operating instructions. Verify the mains voltage matches the drive's input rating (3-phase 400 V class or 3-phase 690 V class).
2. Insert the SAM or IOP-2. Power up the drive. Confirm the on-board LEDs show RUN (green) and no FAULT (red).
3. Use the Web Server (or IOP-2) to perform basic commissioning: motor data, motor identification (p1900 = 1 or 2), control mode (p1300 = 0 for V/f, 20 for sensorless vector), ramp times p1120 / p1121, reference parameters p2000 / p2002 / p2003.
4. Configure the free telegram. In the Web Server parameter list, set p0922 = 999, then set p2051[0..11] and p2061[0..11] as documented in the application's wiring diagram. Save parameters (RAM → ROM, p0971 = 1).
5. Power down and up the drive (or use p0971 = 1) to apply the telegram change. Verify the new layout in r2050 / r2060.
6. In TIA Portal V16, add the G120X to the device configuration (drag from catalog into the PN subnet). Confirm the free telegram 12/12 shows up in the telegram list.
7. Compile and download the hardware configuration to the S7-1515-2 PN. Verify the IO addresses match the expected range (e.g., %IW100..%IW111 and %QW100..%QW111).
8. Create the DB_DriveFreeTlg data block with the WORD-by-WORD structure shown above, then write OB1 to copy the PZD words into the DB.
9. Compile, download, and go online with the S7-1500. Open a watch table on the DB and observe ZSW1 cycling through 16#0B31 → 16#0B37 → 16#0B3F as the drive accepts the ON command.
10. Issue the run command from the HMI or via a debug tag. Observe NIST_A following NSOLL_A after ramp time p1120. Verify the line contactor closes (ZSW1 bit 1) and the motor rotates in the correct direction.
11. Stop the drive, save the project, and back up the drive parameters (Startdrive → "Upload to PG" or Web Server → "Backup parameter to SAM").

Verification Checklist

Troubleshooting Matrix

Safety Integration (STO on G120X)

The G120X does not support PROFIsafe over PROFINET in the basic product. Safe Torque Off (STO) is implemented as a hardwired function on the CU230P-2 control unit through the dedicated STO terminals (typically X9 on the CU). The drive meets SIL 2 / PL d according to IEC 61800-5-2 when the STO inputs are wired through a safety relay or safety PLC. PROFIsafe is supported on the higher-tier SINAMICS S120 and on the G120 with the CU250S-2 control unit, but not on the G120X. Plan the safety architecture accordingly: a fail-safe SIMATIC CPU (e.g., S7-1516F) reads its safety inputs and drives the STO terminals on the G120X through a safety relay or directly through the F-CPU outputs.

The STO terminals must be wired per the operating instructions; typically +24 V is applied to STO+ and STO+ (two redundant channels) to enable torque production. Removing 24 V from either channel removes the gate signals within a few ms and stops the drive safely.

HMI Integration

For a Comfort Panel (TP700 / TP1200) or a WinCC Runtime connected via PROFINET, the HMI polls the same DB_DriveFreeTlg tags. A typical HMI faceplate shows:

• Speed setpoint (REAL, rpm) — derived from NSOLL_A
• Speed actual (REAL, rpm) — derived from NIST_A
• Motor current (REAL, A) — derived from IAIST
• Active power (REAL, kW) — derived from PIST
• Drive status word (bit indicators) — ZSW1 bits 0..15
• Control word override (start, stop, jog, fault ack) — manipulates STW1 bits

The HMI does not access the peripheral IO; all tags are read from the symbolic DB. The HMI also subscribes to the drive's PROFINET alarm (alarm number 0x010A = drive fault alarm) so that fault pop-ups appear in WinCC without polling.

Migration Notes from V17 to V16

If a working V17 project with the Siemens-made free telegram block exists, the block itself is library-protected and cannot be edited or unlocked in V16. Three practical options exist:

1. Keep the V17 project on a separate engineering PC; export the DB tags only and re-import as a UDT in the V16 project. The runtime logic must be re-coded (this article's WORD-split technique).
2. Recreate the block in V16 as a standard FB / DB pair. The free telegram is not algorithmically complex; the IO mapping and STW/ZSW bit handling is the main content, all of which is documented above.
3. Use the Startdrive functionality inside TIA V16 (which is the same as V17 for this purpose): drive → Properties → Communication → Telegram configuration. Set the free telegram there and let Startdrive generate the symbolic tags.

The TIA Portal V16 → V17 migration does not change the runtime behavior of the free telegram. The HSP that defines the G120X device description is the same content; only the Startdrive Add-In revision changes.

Notes on TIA Portal Version Compatibility

• TIA V16 + Startdrive V16: G120X HSP shipped as standard from V16 Update 5 onward.
• TIA V17 + Startdrive V17: same G120X, additional Startdrive blocks for free telegram generation; these are the protected blocks referenced in field report.
• TIA V18 / V19: G120X continues to be supported; firmware ≥ V5.2 required for new safety functions and the updated free telegram generator blocks.
• G120X firmware: ≥ 4.7 SP7 for full PROFINET conformance class C and current PDO mapping rules. Update via Web Server or via Startdrive (online → "Load firmware").