Configuring G120C PROFINET Telegram 999 with S7-1200 in TIA Portal V12

When a SINAMICS G120C PN drive is coupled to a SIMATIC S7-1200 over PROFINET using TIA Portal V12 and STARTER V12, the control engineer is forced to deal with the PROFIdrive telegram model. The drive will not accept any setpoints, run commands, or ramp time modifications from the PLC until the cyclic PZD data has been mapped on both sides and the Control by PLC bit is set in the first control word. This reference walks through the complete commissioning path: telegram selection, hardware configuration, PLC programming, the critical control word bit, and the firmware-dependent handling of ramp-up / ramp-down times.

1. Prerequisites

Before starting, confirm the following software and hardware are installed and visible in the engineering environment:

• TIA Portal V12 SP1 (or later in the V12 line) with the SINAMICS support package installed so that the G120C PN GSD file is available in the hardware catalog.
• STARTER V12 (or Startdrive in TIA V13+) for the off-line drive parameterization and online commissioning.
• SINAMICS G120C PN with firmware V4.6 (or V4.4 with the limitations noted in Section 9).
• SIMATIC S7-1200 CPU with PROFINET interface (CPU 1211C, 1212C, 1214C, 1215C, 1217C, or 1212FC/1214FC/1215FC fail-safe variants are all compatible).
• PROFINET patch cables, switch (or direct device-to-device cabling), and G120C Control Unit with PROFINET connectors.
• Device name assignment mechanism: PRONETA, TIA Topology editor, or the G120C BOP-2 / IOP.

2. PROFIdrive Telegram Model in 90 Seconds

PROFIdrive defines a fixed set of telegrams that determine the order and meaning of the PZD (Process Data) words exchanged cyclically between controller and drive. A telegram contains:

• PZD1 (output, PLC → drive): Control word 1 (STW1).
• PZD2 (output, PLC → drive): Speed setpoint (NSOLL_A), 16-bit normalized value.
• PZD1 (input, drive → PLC): Status word 1 (ZSW1).
• PZD2 (input, drive → PLC): Actual speed value (NIST_A), 16-bit normalized value.

Standard telegrams 1, 2, 3, 4, 20, 352, 354 and the Free Telegram 999 are supported by the G120C. Standard telegrams have fixed content. Telegram 999 is fully user-definable - the engineer maps any available PZD signal to PZD1, PZD2, PZD3, etc.

3. Selecting Free Telegram 999 in TIA Portal V12

1. Open the TIA Portal project and the device configuration of the S7-1200.
2. Locate the G120C PN in the network view and open the device properties.
3. Switch to Device View > Properties > PROFINET interface > Telegram configuration.
4. From the dropdown, change the default telegram to Standard telegram 999 (extended).
5. The slot list becomes editable. The default TIA Portal V12 configuration for G120C populates a 6/6 PZD layout:

To make the additional parameters (direction, ramp times) available cyclically, populate the free slots with the relevant signal numbers. The Siemens application example 68034568 documents the full signal list. Typical mapping for a four-word cyclic frame:

• PLC → Drive PZD3: Ramp-up time (signal 0x0144 / p1138)
• PLC → Drive PZD4: Ramp-down time (signal 0x0145 / p1139)

The signal numbers are the parameter index in the lower byte and the WORD marker (0x01) in the upper byte. After editing the slot list, compile the project so that the I/O addresses are recomputed and displayed in the device view.

4. Reading the I/O Address Map

After the compile step, TIA Portal assigns an I/O address range. The example used here produces:

5. Configuring the G120C in STARTER V12

1. Open STARTER V12 and connect online to the G120C over PROFINET (TCP port 2407 default, or via the routing table once the device name is assigned).
2. Open the project that was created when the drive was inserted into the TIA Portal network view. The Insert SINAMICS drive wizard automatically creates a STARTER-compatible archive.
3. Navigate to Configuration > Telegram configuration and confirm the same telegram 999 layout that was defined in TIA Portal. STARTER will re-read the slot list from the drive's parameter p922.
4. Verify the PROFIdrive parameters:
   • p922 = 999 (telegram selection)
   • p2051[0..15] (PZD output signals to the drive)
   • p2050[0..15] (PZD input signals from the drive)
   • p0922 = ... IF1 PROFIdrive PZD telegram selection
5. Save and download to the Control Unit, then perform a power-cycle or a warm restart if STARTER prompts for one.

6. Control Word 1 and the Bit 10 Permissive

The single most common reason that writes from the PLC appear to have no effect on the drive is that STW1 bit 10 is not set. The G120C, like every SINAMICS drive implementing PROFIdrive profile 3 (Velocity Mode), requires this bit to confirm that the controller is the active master.

A typical run word to start the drive in the forward direction at the speed setpoint is 16#047F (binary 0000 0100 0111 1111). For reverse operation use 16#0C7F (bit 11 set) or 16#087F if the application uses an inverted bit-11 polarity.

Without bit 10 the drive will not enter Operation enabled state (ZSW1 bit 2 = 0), and the cyclic PZD writes are silently ignored. STARTER's online watch table will show STW1 with bit 10 = 0 even when the PLC is moving a value to %QW68; the diagnostic is unambiguous when you add the control word to the expert list and read p2051[0].

7. PLC Programming: Reading and Writing PZD in SCL or LAD

For the simple case of writing a fixed control word to PZD1, the standard MOVE instruction is sufficient. The MOVE instruction performs a direct load from a tag to the assigned output address, and the PROFINET stack on the S7-1200 takes care of the cyclic transmission. Example in LAD:

// Data block "DriveControl"
// Tag:    stw1 : WORD    // Control word 1
// Tag:    nsoll : INT    // Speed setpoint (-32768 .. +32767 => -100% .. +100%)

// Network 1 - Build STW1
// Bits: ON(0) | OFF2(1) | OFF3(2) | Enable(3) | RG-EN(4) | RG-Start(5) | SP-EN(6) | Ack(7) | 0(8) | 0(9) | PLC-Ctrl(10) | Dir(11) | 0(12..15)
// Forward run with PLC control: 16#047F
// Reverse run with PLC control: 16#0C7F
L 16#047F            // hard-coded forward run
T "DriveControl".stw1

// Network 2 - Build NSOLL_A (normalized)
L 10000              // 10000 decimal = ~30.5% of p2000 reference speed
T "DriveControl".nsoll

// Network 3 - Write to PZD output words
MOVE   "DriveControl".stw1  -> %QW68
MOVE   "DriveControl".nsoll -> %QW70

// Network 4 - Read PZD input words into tags
MOVE   %IW76 -> "DriveControl".zsw1
MOVE   %IW78 -> "DriveControl".nist

For higher-integrity applications, or when the S7-1200 has the PROFINET IRT option, prefer the system function blocks DPRD_DAT (read) and DPWR_DAT (write). These blocks provide consistent data transfer and status information. The application example at Siemens Entry ID 68034568 includes a fully-tested SCL library that wraps these blocks for SINAMICS drives.

For parameters that are not part of the cyclic telegram (any parameter not mapped to a PZD slot), use the acyclic mechanism with RDREC and WRREC. The G120C parameter index is constructed as (parameter number * 0x10000) + (sub-index * 0x100) + data_length_in_bits. The slot is the PROFINET slot of the drive submodule; for the G120C this is typically slot 1.

8. Direction of Rotation Handling

The direction of rotation is controlled by STW1 bit 11. For a single-bit interpretation:

• 0 = positive direction of rotation (forward, per p1113 setting)
• 1 = negative direction of rotation (reverse)

The reference direction is configured in p1113 in STARTER. If the application must block reverse operation, the corresponding interlock should be written into the PLC logic before STW1 is assembled; the drive itself does not enforce direction by default.

When both direction reversal and an analog setpoint polarity inversion are required, the simplest path is to leave NSOLL_A as a signed integer and combine the direction with the sign of the setpoint. A negative NSOLL_A in conjunction with bit 11 = 0 is treated as a positive setpoint by the drive, so the sign of the setpoint is overridden by the bit-11 value.

9. Ramp Time Handling on Firmware V4.6 and Later

With SINAMICS G120C firmware V4.6 the ramp times can be adapted cyclically as PZD words. The signals are exposed in the parameter list as:

When the application requires continuous adjustment of the ramp time, map the signal to an output PZD slot. The S7-1200 then writes a WORD value where 1 corresponds to 10 ms. A value of 100 yields a 1.00 s ramp. Note that the drive interprets a value of 0 as the minimum ramp (typically 0.01 s), so the PLC must clamp the value to a sensible lower bound.

10. Acyclic Parameter Access (WRREC / RDREC)

When a parameter is not part of the cyclic telegram 999, the PLC uses the PROFINET acyclic channel. The Siemens application example 68034568 provides ready-made function blocks Sinamics_Write and Sinamics_Read for the S7-1200 / S7-1500. The request structure for WRREC is:

// Data block of type "Sinamics_WRREC".req
//   Slot          := 1;            // PROFINET slot of the G120C
//   Index         := 16#0113;      // = (1138 * 0x10000) + (0 * 0x100) + 16 (16 bits)
//   DataLength    := 2;            // bytes (WORD)
//   Data          := 16#0064;      // 100 dec = 1.00 s ramp-up
//   Done          := ...;          // output
//   Busy          := ...;          // output
//   Error         := ...;          // output
//   Status        := ...;          // output

The standard Siemens request header for a parameter access is 4 bytes (R/W + parameter number + sub-index) and is followed by the data. The full index formula:

Index = (param_number << 8) | (sub_index << 0)        // for request header
       + (data_length_bits / 8) << 16                 // for the length field

When the field engineer writes a parameter with WRREC, STARTER will show the new value in the expert list almost immediately, confirming that the access succeeded.

11. Fault Code F08501 and Stop-Mode Behavior

When the S7-1200 is switched to STOP, the PROFINET cyclic frames cease. The G120C detects the loss of cyclic communication after a configurable watchdog interval (default 3 × PROFINET update time, e.g. 36 ms at 12 ms update rate) and raises the fault F08501 (PROFIdrive communication error) or F08502 (PROFINET sign-of-life failure), depending on the parameter setting p2048.

This is the expected response and is not a configuration error. To suppress a fault trip on PLC stop, the application has two paths:

1. Set p2048 = 0 to disable the sign-of-life monitoring on the drive (not recommended for safety-related applications).
2. Configure the S7-1200 OB1 / Startup so that the PZD output words continue to be written with safe values (e.g. STW1 = 16#047E to keep bit 0 OFF while bit 10 is still set) before the controller transitions to STOP. This is achieved with an OB100 / warm restart that pre-loads the output process image.

12. Common Pitfalls and Diagnostic Steps

13. Commissioning Procedure - Field-Tested Sequence

1. Wire the G120C PN to the S7-1200 PROFINET port. Assign a unique device name with PRONETA, the TIA Topology editor, or the BOP-2.
2. In TIA Portal, insert the G120C PN from the hardware catalog. Configure the PROFINET interface with the assigned device name and IP address.
3. Set the telegram to Standard telegram 999 (extended). Populate PZD3 and PZD4 with the ramp time signal numbers (0x0144 and 0x0145) if FW V4.6 is in use.
4. Compile the project and download the hardware configuration to the S7-1200.
5. Open STARTER V12 (or Startdrive from TIA Portal). Connect online to the G120C, verify p922 = 999, p2051[0..5] and p2050[0..5] match the TIA configuration.
6. Download the drive parameters. Power cycle the Control Unit if requested.
7. Go online with the S7-1200. Add a watch table on the PZD output and input addresses. Force STW1 = 16#047F and NSOLL_A = 0.
8. Confirm the drive responds: ZSW1 bit 2 (Operation enabled) should go to 1 and ZSW1 bit 0 (Ready to switch on) should be 1. NIST_A should track NSOLL_A.
9. Step the speed setpoint from 0 to a small positive value (e.g. 2000 decimal = ~6%). The motor should ramp up.
10. Toggle bit 11 of STW1 to verify direction reversal. The motor should ramp down to 0 and then accelerate in the opposite direction.
11. Write a new ramp time (PZD3 or PZD4) and verify the change in p1138 or p1139 in STARTER.

14. Verification Checklist

• [ ] Device name and IP address are unique and reachable from the S7-1200.
• [ ] Telegram 999 in TIA matches p922 in STARTER.
• [ ] p2051[0] = 0x0100 (STW1) and p2050[0] = 0x0200 (ZSW1) on the drive.
• [ ] I/O addresses (e.g. %QW68, %IW76) appear in the device view and match the PLC program.
• [ ] STW1 bit 10 = 1 in every cycle (use a watch table cross-check).
• [ ] ZSW1 bit 2 = 1 (Operation enabled) when ON is commanded.
• [ ] ZSW1 bit 3 = 0 (No fault) before commanding a run.
• [ ] NIST_A tracks NSOLL_A within the configured ramp time.
• [ ] Direction reversal: STW1 bit 11 toggles NSOLL_A sign internally; motor ramps through zero.
• [ ] Ramp time changes: PZD3/PZD4 writes show up in p1138 / p1139 within one PROFINET cycle.

15. Related Standards and Documentation

Engineers commissioning this configuration should consult:

• PROFIdrive profile 3 (Velocity Mode) - the application class on which STW1 / ZSW1 is defined. Refer to the PROFIBUS Nutzerorganisation (PNO) profile document.
• IEC 61800-7 - Adjustable speed electrical power drive systems, the umbrella standard that defines the cyclic data interface.
• SINAMICS G120C Operating Instructions - the parameter list with all signal numbers referenced in telegram 999.
• S7-1200 System Manual, Chapter on PROFINET - the I/O addressing model and the use of MOVE vs system function blocks.