Configuring PROFIsafe with S7-1500F and SINAMICS G120 Drives

PROFIsafe is the open safety bus profile that runs over PROFINET (or PROFIBUS) and provides black-channel communication between a fail-safe controller (F-Host) and fail-safe field devices (F-Devices) without requiring any special safety-rated network hardware. This reference documents a typical architecture built around an S7-1500F controller, ET 200SP F-modules, and SINAMICS G120 drives, and answers the recurring engineering questions about switch selection, mixed-topology daisy chaining, memory cards, and the trade-off between StartDrive and GSDML-based drive integration.

1. PROFIsafe Protocol Foundation

PROFIsafe is defined in IEC 61784-3-3 as Profile for Functional Safety on PROFIBUS and PROFINET (CPF 3). The current profile generation, PROFIsafe V2.6.1, supports both PROFINET and PROFIBUS transports and uses a 4-byte CRC (CRC2) over the user payload plus a 1-byte status/control byte to detect:

• Repetition, loss, insertion, incorrect sequence
• Masquerading, corruption, delay (watchdog)
• Incorrect addressing

The safety protocol is encapsulated inside standard PROFINET IO frames (RT or RT_CLASS_3) and uses PROFINET slot addressing. Because PROFIsafe is a black-channel profile, every standard PROFINET-compliant device in the path is permitted as long as it does not modify or drop safety frames. This is why a non-safety-rated SCALANCE switch can carry PROFIsafe traffic without losing the safety integrity.

The PROFIsafe profile page at profibus.com is the authoritative source for profile versions, conformance test specifications, and the F-Parameter description.

2. PROFINET Network Topology for PROFIsafe

PROFINET permits line, star, tree, and ring topologies. PROFIsafe places no additional constraint on the chosen topology beyond the requirements that already apply to standard PROFINET IO:

• Maximum hop count and switch latency must keep the worst-case PROFIsafe frame within the configured F-Watchdog (F_WD_Time).
• Cable-based or fiber-optic transmission must satisfy PROFINET installation guidelines for the chosen conformance class (CC-A, CC-B, CC-C).
• Switches must not apply PROFINET frame manipulation, priority downgrades, or store-and-forward blocking that would violate the watchdog.

2.1 Conformance classes relevant to safety networks

PROFIsafe can be used on any of these classes provided the F_WD_Time is dimensioned wide enough for the worst-case transit.

3. SCALANCE Switch Behavior in PROFIsafe Networks

A standard SCALANCE switch (XC, XB, XR, or XM series) does not require any special configuration or firmware to carry PROFIsafe frames. The PROFINET standard already provides the QoS priority bits that the F-Host and F-Device use to identify safety frames, and the switch forwards them as ordinary VLAN-priority-tagged PROFINET RT frames.

3.1 Practical switch settings

• VLAN priority 6 (and where used, 7 for high-priority diagnostics) must be passed through the switch unchanged. SCALANCE switches do this by default.
• Broadcast storm protection should remain enabled but with a generous threshold; the safety watchdog must be sized to absorb storm-recovery time.
• Port-based or MAC-based access control lists should not block PROFINET multicast or the F-Device MAC/IP.
• Port speed and duplex must be matched; autonegotiation should remain enabled unless the PROFINET device requires a fixed setting.

Use of an SCALANCE switch does not change the SIL claim, PL, or category of the safety function. The safety case is established by the F-Parameters, F-Host configuration, and F-Device conformity, not by the transport switch.

4. Mixed Safe and Non-Safe Device Daisy Chaining

PROFIsafe and standard PROFINET IO can coexist on the same physical network and even on the same line. A typical mixed daisy chain looks like:

S7-1516F/ET 200SP F-CPU -> SCALANCE -> ET 200SP F-DI/F-DO (PROFIsafe) ->
SINAMICS G120 CU240E-2 PN-F (PROFIsafe) -> SINAMICS G120 CU240E-2 PN (standard PROFINET) -> ET 200SP standard module

The rules to respect:

1. Only one F-Host per PROFINET subnet is allowed; this is the F-CPU in the S7-1500F rack.
2. Each F-Device must be assigned a unique PROFIsafe destination address (F_Dest_Add) within the range 1..65534.
3. Standard PROFINET devices and PROFIsafe devices share the same broadcast domain, so any broadcast storm affects both.
4. The F-Host's PROFINET IO configuration must include every F-Device with its F-Parameter set and a PROFINET slot mapping for the PROFIsafe slot (typically slot 0 subslot 1, with the actual user data in higher subslots).

Daisy chaining a safe drive next to a non-safe drive is supported. PROFIsafe frames only travel between the F-Host and the F-Device; the intermediate non-safe device simply forwards PROFINET frames transparently because it operates as a PROFINET IO-Device with no PROFINET IO-Controller function (unless it is an IO-Controller in its own right, in which case it cannot appear in the same line without proper routing).

5. S7-1500F Controller Configuration

The F-CPU must be selected from the SIMATIC S7-1500F range:

The safety program is part of the same S7-1500F user program but is compiled into a separate F-Container. The F-Container is signed and protected by the safety password (or safety printout/CRC) defined in the F-Configuration. Activation of the safety mode requires that the safety signature matches the value stored in the F-CPU.

5.1 F-Block types used in the safety program

• F_IO_C: F-IO-Controller block for exchanging fail-safe IO data with an F-Device.
• F_DB: Fail-safe instance DB storing the F-IO signature.
• F_RTG: Runtime group that defines the safety cycle (F-Cycle time, F-WD_Time).
• F-PB / F-CTD / F-ESTOP / F-FDB: certified safety blocks for E-STOP, two-hand, muting, etc.

The F-Cycle time (F-CPU cycle of the safety task) is typically 10 ms for fast E-STOP functions but can be relaxed to 50-100 ms for slower SLS or SLP loops to reduce load on the F-CPU.

6. ET 200SP F-Module Integration

The ET 200SP distributed IO system is the natural partner for an S7-1500F on the field side. F-Modules are inserted into standard ET 200SP BaseUnits and behave as F-Devices on PROFINET (or PROFIBUS with the right head module).

6.1 Common F-Modules

Each F-Module is configured in TIA Portal under Devices & Networks > PROFINET IO > F-Device. The PROFIsafe address (F_Dest_Add) is set either via DIP switches on the module (older F-Modules) or via PROFINET DCP after device replacement without programming device.

7. SINAMICS G120 PROFIsafe Drive Integration

The SINAMICS G120 modular drive system comprises a Power Module (PM) plus a Control Unit (CU). For PROFIsafe over PROFINET, the Control Unit must support PROFINET IO and Safety Integrated (or PROFIsafe in the profile-specific slot).

7.1 Safety Integrated functions on SINAMICS G120

The extended functions (SLS, SDI, SS2, SOS) require a CU250S-2 Control Unit with firmware 4.7 SP3 or later. Basic STO and SS1 via PROFIsafe are available on the CU240E-2 PN-F and CU250S-2 PN(-F) variants.

8. Drive Control Unit MLFB Reference

The user-supplied MLFBs identify the specific Control Units in the project. Both are PROFINET-capable Control Units that integrate into a TIA Portal project with StartDrive.

Verify the precise firmware loaded on each Control Unit during commissioning. SINAMICS G120 Control Units are usually shipped with a recent firmware; use StartDrive V13 SP1 UPD3 (or the current TIA Portal version) to read the firmware version and trigger an update if required. With StartDrive V13 SP1 UPD3 the supported drive firmware is V4.7 SP3, which is the recommended baseline for new projects.

9. Memory Card and Firmware Management

SINAMICS G120 Control Units have built-in non-volatile flash memory that holds the parameter set and the active firmware. A memory card is not required for normal operation.

9.1 When a memory card is needed

• Firmware update: The new firmware file (e.g., FW_G120_CU2x0-2_V4_7_3.bin) is loaded from a SINAMICS SD card.
• Parameter backup: A complete parameter set can be stored on the SD card for device replacement without programming device.
• Series commissioning: Cloning the configuration to multiple identical drives.
• License transfer: For licensed options.

9.2 Recommended memory card

Drive-side firmware updates do not require the SD card if the firmware is loaded through PROFINET/Web Server using StartDrive; the SD card is the fallback method for offline updates in the field.

10. StartDrive vs GSDML Configuration Strategy

Two integration paths are available in TIA Portal:

10.1 StartDrive path (preferred for SINAMICS G120)

• Add the Control Unit from the Siemens catalog in TIA Portal under Drives & starters > SINAMICS G120.
• Configure the Power Module, encoder option, I/O extension, and Safety Integrated functions directly in TIA Portal.
• The drive appears as a PROFINET IO-Device with PROFIenergy, PROFIsafe, and cyclic PROFINET data.
• Online commissioning, trace, and fault diagnostics are all available from the same TIA Portal project.

10.2 GSDML path (legacy or non-StartDrive projects)

• Install the GSDML file for the drive (for example G120_V4.7_SP3.xml).
• Configure the drive as a generic PROFINET IO-Device.
• Parameterization and commissioning must be done in STARTER (or Startdrive stand-alone) outside TIA Portal.
• This path is used when the TIA Portal version does not yet include the G120 firmware revision, or for legacy hardware.

For a project on TIA Portal V13 SP1 or newer, StartDrive is recommended because it keeps the F-Host, F-Devices, and the drive configuration in a single, consistent project. Mismatches between the GSDML revision and the actual drive firmware version often produce slot mismatches at runtime; StartDrive resolves these automatically.

11. F-Parameter Configuration in TIA Portal

Every PROFIsafe relationship between the F-Host and an F-Device carries a fixed parameter set. In TIA Portal these are entered in the Inspector window under Properties > PROFIsafe for the F-Device slot.

11.1 F_WD_Time sizing

The minimum F_WD_Time must cover the worst-case PROFINET frame round-trip plus the F-Device processing time. A practical formula:

F_WD_Time_min = 2 * (T_cycle + T_diag_ack) + T_F-Device_proc

Where:

• T_cycle = PROFINET update time for the F-Device slot (configured in TIA Portal under PROFINET interface > Update time)
• T_diag_ack = diagnostic acknowledge latency (depends on topology, switch count, line length)
• T_F-Device_proc = F-Device internal processing time (typically 5-20 ms for SINAMICS G120)

Example: PROFINET update 4 ms, line of three switches with 1 ms each, F-Device processing 10 ms, plus a 100% safety margin for retries:

F_WD_Time_min = 2 * (4 + 6) + 10 + 100% margin = 40 ms
Rounded up to nearest multiple of 10 ms -> F_WD_Time = 50 ms

12. Commissioning Procedure

1. Wire and power up: Connect S7-1500F, SCALANCE switches, ET 200SP F-Modules, and SINAMICS G120 Control Units. Verify all PROFINET LEDs are green before continuing.
2. Open the TIA Portal project: Add the S7-1500F as the IO-Controller. Add each F-Module and each G120 Control Unit (StartDrive) as IO-Devices.
3. Assign device names and PROFINET addresses: Use Online > Accessible Devices or Topology Editor. Assign a unique PROFINET name and IP to every node.
4. Configure F-Parameters: In the Inspector for each F-Device, enter F_Dest_Add, F_Par_Version, and let TIA Portal compute F_Par_CRC. Set F_WD_Time per the formula above.
5. Compile the safety program: Use the safety printout/CRC workflow. Document the F-Container signature.
6. Download to the F-CPU: First download the standard project, then download the safety program. The F-CPU prompts for the safety password.
7. Accept safety commissioning: In TIA Portal > Online > Safety, run the acceptance test wizard.
8. Drive commissioning: With StartDrive, drive online and run the basic commissioning wizard (motor data identification, encoder, current limits). Then enable Safety Integrated and PROFIsafe.
9. Verify PROFIsafe channels: Force each safe input and observe the safe output and STO/SS1 reaction on the drive. Log the reaction time.
10. Sign and archive: Save the signed project and the safety printout to the machine documentation.

13. Diagnostics and Troubleshooting

PROFIsafe errors manifest as F-Host faults (F-Stop) or drive faults (F01910, F01911, F08501, etc. on SINAMICS). Common patterns:

14. Verification Checklist

• ☐ F-CPU type and MLFB confirmed (SIL 3 / PL e / Cat. 4)
• ☐ F-Devices have unique F_Dest_Add values
• ☐ F_Par_Version matches every F-Device firmware
• ☐ F_WD_Time exceeds worst-case round trip including MRP reconfiguration
• ☐ SCALANCE switch is on supported PROFINET conformance class
• ☐ PROFINET update times are matched across F-Devices
• ☐ SINAMICS G120 Control Units show firmware V4.7 SP3 or newer
• ☐ STO/SS1 source on drive is set to PROFIsafe
• ☐ Safety printout stored in machine file
• ☐ Acceptance test signed and archived
• ☐ Backup of drive parameter set stored on SD card or StartDrive project

15. Field-Proven Caveats

• PROFINET update time of 1 ms on every F-Device is not always necessary and can lead to F-Host overload; 4-8 ms is a better starting point unless reaction time is constrained.
• The PROFINET device name is case-sensitive and PROFINET topology discovery will fail silently on a typo.
• MRP manager role should be assigned to the F-CPU or a dedicated managed switch, not to the SINAMICS G120, which is best left as MRP client to keep recovery time predictable.
• If the drive firmware is older than V4.7 SP3, the F-Container signature generated by StartDrive V13 SP1 UPD3 may be rejected; update the drive firmware first.
• StartDrive in TIA Portal V13 SP1 is the last release that uses the legacy HSP. From V14 onward, StartDrive HSP or add-in packages are required.

FAQ