Connecting a SINAMICS G120 to a SIMATIC S7-1200 over PROFINET in TIA Portal

This reference walks through every step required to put a SINAMICS G120 frequency converter on PROFINET with a SIMATIC S7-1214 CPU. It covers the hardware that must be present, the G120 control-unit and power-module combinations that are supported, the exact TIA Portal path to add the drive, the PROFINET device name rules, the choice of standard telegram, two valid programming paths (the driveLib / SINA_SPEED blocks for older firmware, and the native Technology Object Axis for firmware V4.0 and later), and a troubleshooting matrix for the faults most often seen during commissioning.

1. Prerequisites

Verify the SINAMICS G120 entry in the TIA Portal hardware catalog before commissioning. In the Network view the drive should appear under Other field devices → PROFINET IO → Drives → Siemens → SINAMICS (per the TIA Portal S7-1500 manual collection - Configuring SINAMICS G120). If the drive is missing, the GSD has not been installed for the current TIA Portal version.

2. Hardware Topology and Wiring

The G120 with a CU240B-2 PN or CU240E-2 PN has two PROFINET ports (P1, P2) on the bottom of the control unit. Use them to daisy-chain other PROFINET nodes or to form a line topology with the S7-1200 as the IO controller.

1. Mount the PM240-2 power module on the panel backplate, snap the CU240B-2/E-2 PN on top. The control unit is hot-pluggable; the power module is not.
2. Wire the three-phase supply (L1, L2, L3, PE) to the PM240-2 input terminals and the motor U, V, W, PE to the output. The shield of the motor cable must be bonded to the drive's PE terminal with a 360° clamp.
3. Connect PROFINET port P1 of the G120 to the S7-1214 PROFINET port (X1) using an industrial Ethernet cable. If you are daisy-chaining, P2 of the G120 feeds the next node.
4. Wire a digital input (e.g. DI0) of the CU to a hardware enable / OFF1 source if the standard telegram uses bit 0 of STW1 for ON/OFF1.
5. Wire the STO (Safe Torque Off) inputs on the CU240E-2 PN if you intend to use integrated safety. CU240B-2 PN does not support STO; it requires an external safety relay or a higher-level safety CPU.

3. TIA Portal Project Structure

1. Open TIA Portal and create a new project. Add the S7-1214 CPU with the correct order number and firmware version (Devices & networks → Add new device).
2. In Devices & networks switch to the Network view.
3. Open the Hardware catalog task card on the right side, navigate to Other field devices → PROFINET IO → Drives → Siemens → SINAMICS and drag the G120 device that matches the control unit you are using (CU240B-2 PN or CU240E-2 PN) into the network view.
4. Click the green PROFINET port on the CPU and the green PROFINET port on the G120 to draw the IO connection. TIA Portal assigns the IO controller/IO device relationship automatically.
5. Open the G120 device view. The slot "Telegramm" (slot 0, subslot 1) is the place where the cyclic PZD telegram is selected.

4. Assigning the PROFINET Device Name

The PROFINET device name is what the IO controller uses to address the G120 during AR (Application Relationship) establishment. Two facts that often trip up first-time users:

• You may enter the name in TIA Portal in upper-case, lower-case, or mixed case. The engineering tool does not enforce a case.
• The SINAMICS G120 stores the assigned name internally in lowercase only. If you assigned "G120-DRIVE-01" in TIA Portal, the device will store it as "g120-drive-01". PROFINET name comparison is case-insensitive, so the AR will still come up.

To assign the name to the physical device, right-click the G120 in the network view and select Assign PROFINET device name. Confirm the MAC address matches the sticker on the CU, then click Assign name. The "Search" function in this dialog will only show devices that have no name or whose name does not match a configured partner; it is normal for an already-assigned drive to be invisible until the filter is changed.

5. Telegram Selection

The cyclic PZD telegram defines the layout of the process data that is exchanged every PROFINET cycle. The G120 with CU240B-2/E-2 supports the following standard telegrams (selection in slot 0, subslot 1 of the device view):

For a first integration on the S7-1200, pick telegram 1 (default) or telegram 2. Telegram 1 fits the S7-1200 Motion Control axis (TO_Axis_PTO or TO_SpeedAxis) for firmware V4.0 and later. Telegram 2 fits the classic driveLib / SINA_SPEED blocks for older firmware. The S7-1200 always communicates on 16-bit boundaries, so the IO data width must be a multiple of two words.

6. Programming Path A — driveLib / SINA_SPEED (Firmware V3 and Earlier)

For a S7-1200 with firmware V3 or a project that needs fine control over the control word and status word, the Siemens example project 70155469 provides a library of function blocks built on top of SINA_SPEED (FB 285). The blocks ship in the Drive_Lib_S7_1200_1500 library and abstract the packing/unpacking of NSOLL_A / NIST_A.

Minimum tag map (telegram 1) in the S7-1200 I/O image:

• Inputs: IW64 — ZSW1 (status word 1), IW66 — NIST_A (actual speed, normalised)
• Outputs: QW64 — STW1 (control word 1), QW66 — NSOLL_A (speed setpoint, normalised)

Control word 1 (STW1) bit assignments that must be set to start the drive:

• Bit 0 = ON / OFF1 (rising edge latches)
• Bit 1 = OFF2 (1 = no coast stop, must be held high)
• Bit 2 = OFF3 (1 = no quick stop)
• Bit 3 = Enable operation (pulse enable)
• Bit 4 = Enable ramp generator
• Bit 5 = Unfreeze ramp generator / continue
• Bit 6 = Enable speed setpoint
• Bit 10 = Control by PLC (must be 1)

Typical start sequence in SCL on the S7-1200:

// Drive control word sequence
IF bStart AND NOT bFault THEN
    stw1.%X0  := TRUE;   // ON / OFF1
    stw1.%X1  := TRUE;   // No coast stop
    stw1.%X2  := TRUE;   // No quick stop
    stw1.%X3  := TRUE;   // Enable operation
    stw1.%X4  := TRUE;   // Enable ramp generator
    stw1.%X5  := FALSE;  // Freeze ramp generator (no-op at start)
    stw1.%X6  := TRUE;   // Enable setpoint
    stw1.%X10 := TRUE;   // Control by PLC
ELSE
    stw1 := 16#047E;     // Operational disable pattern: bit0=0 (OFF1), bit1=0 (OFF2)
END_IF;

// Speed setpoint, normalised to 0x4000 = 100 %
iSpeedSetpoint := REAL_TO_INT(fSpeedPercent * 163.84);

7. Programming Path B — Technology Object Axis (Firmware V4.0+)

From CPU firmware V4.0, the S7-1200 supports a Speed axis or Positioning axis technology object (TO) that can be linked to a PROFINET drive using a standard telegram directly. The TO handles the STW1 bit pattern, ramp generation, and the limit switches, so the application code no longer needs to pack/unpack the process data.

1. In the project tree, expand Technology objects → Add new object → Motion Control → TO_SpeedAxis.
2. In the axis configuration, set Drive → Drive type to "PROFIdrive / PROFINET drive".
3. Select the G120 IO device that is already inserted in the network view, and assign the telegram that the drive is configured for (1 or 2).
4. Configure Mechanical: lead screw pitch or load gear ratio, maximum speed, direction of rotation.
5. Configure limits: software limit switches (where applicable), jerk limit, emergency stop deceleration.
6. Call MC_Power in OB1 with the axis DB, then MC_MoveVelocity or MC_MoveRelative to command motion. The TO will write the appropriate STW1 and NSOLL_A words automatically.

8. Commissioning the Drive Side

Before going on PROFINET, the G120 must be commissioned with the SINAMICS Startdrive commissioning tool (or the BOP-2 / IOP-2 on the drive) so that the motor data, current limits, ramp times, and command sources match the application.

1. Perform a quick commissioning (p0010 = 1) from the BOP-2: enter motor voltage, current, power, cos φ, and frequency from the motor nameplate. The drive will auto-calculate the field-weakening and current controller parameters.
2. Set p0700 = 6 (command source = PROFINET / fieldbus) and p1000 = 6 (setpoint source = PROFINET / fieldbus) so that the cyclic telegram is the active source.
3. Set p0922 = 1 (or the telegram number selected in TIA Portal) to enable the matching standard telegram.
4. Run motor identification (p1900 = 2) at the next ON command so the current controller and encoder model are tuned to the connected motor.
5. Save with p0971 = 1 so parameters survive a power cycle.

9. Verification Checklist

After downloading the TIA Portal project and the SINAMICS parameters, verify the following in this order:

1. Online → Accessible nodes shows the S7-1214 and the G120 with their respective IP addresses and the assigned PROFINET name.
2. On the G120, r0021 (PROFINET state) shows "Connected" / r0899 (operating display) shows the expected operating mode.
3. The S7-1200 diagnostics buffer (Online & diagnostics → Diagnostics buffer) contains no PROFINET IO fault entries. A typical fault is "IO device failure" (Event ID 0x013C) which usually means a name mismatch or an offline Telegram setting.
4. Force QW64 = 16#047E and observe that the G120 status word returns 0x0E31 (Ready to switch on, switched on, operation enabled, status healthy). A return of 0x0E34 indicates a fault is active — read the drive's r0947 fault code via the Starter / Startdrive online trace.
5. Set QW66 = 16#4000 (50 % speed) and confirm the motor accelerates to half the configured maximum at the configured ramp rate.
6. Drop QW64 to 16#047E and confirm the motor ramps down on OFF1 and not on OFF2 / coast stop.

10. Troubleshooting Matrix

11. Sample Tag Mapping Reference

The following table summarises the default process data mapping for telegram 1 and 2 on the G120 with a CU240B-2 / CU240E-2 PN. The addresses shown are relative to the IO start address configured in TIA Portal — substitute the base for your own project.

12. Frequently Asked Questions