Configuring PROFIsafe Telegram 30 for SINAMICS Drives in SIMATIC PCS 7 F-Systems

In SIMATIC PCS 7 projects using S7 F-Systems without the Drive ES library, failsafe control of SINAMICS drives—such as Safe Torque Off (STO) and Safe Stop 1 (SS1)—is achieved by configuring PROFIsafe Telegram 30 in HW Config and mapping safety control and status bits in CFC using failsafe channel driver blocks from the S7 F-Systems library. Standard process control is handled by standard telegrams (such as Telegram 20 with FbDrive), while safety interlocking directly manipulates Telegram 30 bit structures via F_CH_BO failsafe channel drivers.

PROFIsafe Telegram 30 Structure and Drive Safety Functions

Modern SINAMICS variable frequency drives (such as G120, G120C, and S120) support integrated safety functions governed by IEC 61508 / ISO 13849. To interface these drives with a SIMATIC S7-400F/FH controller in PCS 7, communication is split into two distinct logical channels:
1. Standard Process Telegram: Typically Telegram 1 or Telegram 20, exchanged cyclically with standard process blocks (such as APL FbDrive and MotSpdCL) to manage speed setpoints, start/stop commands, and operating diagnostics.
2. PROFIsafe Telegram 30: A dedicated failsafe telegram consisting of one failsafe control word (F-STW) and one failsafe status word (F-ZSW), wrapped within the PROFIsafe safety communication layer (CRC, monitoring time, and sequence counter).

Telegram 30 enables failsafe commands—including Safe Torque Off (STO), Safe Stop 1 (SS1), and Safe Brake Control (SBC)—to be commanded directly from the PCS 7 safety shutdown matrix without hardwired safety relays.

Hardware Configuration and Safety Addressing in STEP 7

To configure the PROFIsafe communication channel in HW Config:

Insert Drive into Hardware Network: Insert the SINAMICS drive object (G120/S120) onto the PROFIBUS DP or PROFINET IO line.
Configure Standard Telegram: Insert the primary cyclic telegram (e.g., Telegram 20) in slot 1.
Insert PROFIsafe Telegram 30: Add PROFIsafe Telegram 30 to the drive sub-slots.
Assign Failsafe I/O Addresses: Assign input and output memory ranges within the designated failsafe I/O address area (e.g., IB 512..517 and QB 512..517).
Configure PROFIsafe Parameters:
- F_Dest_Add: Assign a unique failsafe destination address. This numerical value must match the safety address set in the drive firmware parameters via STARTER or Startdrive (p9610 / p9810).
- F_WD_Time: Define the PROFIsafe watchdog monitoring time (typically 150–300 ms, depending on fieldbus cycle time).
Compile HW Config: Save and compile the hardware configuration to generate system data blocks.

CFC Engineering with S7 F-Systems Channel Blocks

In S7 F-Systems, block communication differs from standard Step 7 code because safety data cannot be manipulated using arbitrary elementary types. Safety channels must be processed via certified F-channel driver blocks:

Insert F-Channel Drivers: From the S7 F-Systems Lib, place F_CH_BO (Failsafe Channel Driver for Boolean Outputs) or F_BO_FBO blocks into a designated F-runtime group in CFC.
Interconnect Safety Output: Connect the failsafe shutdown logic (e.g., output of an emergency stop matrix F_ESTOP) to the input of F_CH_BO.
Address Telegram 30 Bits: Connect the VALUE output of the F_CH_BO block to the specific bit of the PROFIsafe output address (for example, %Q512.0 for STO).
Generate Safety Module Drivers: During CFC compilation, ensure the option Create module drivers is selected. The compiler automatically instantiates the failsafe driver blocks (F_MOD_ACT) that manage the PROFIsafe protocol wrapper and module passivation monitoring.
Acknowledge Drive Passivation: Map a failsafe reintegration acknowledge signal (F_ACK_REI) to clear passivation after a fieldbus fault or drive power cycle.

Telegram 30 Bit Mapping and Safety Signals

The following table details the standard bit assignments for PROFIsafe Telegram 30:

DirectionBit OffsetSignal NameDescriptionInverted Logic (Safe State = 0)Control (PLC -> Drive)Bit 0STO / SS1Safe Torque Off / Safe Stop 1 activation commandYes (0 = Initiate Safety Trip)Control (PLC -> Drive)Bit 1SS2 / SOSSafe Stop 2 / Safe Operating Stop activation commandYes (0 = Initiate Safety Stop)Control (PLC -> Drive)Bit 2SLSSafely-Limited Speed selection bitYes (0 = Activate Speed Limit)Control (PLC -> Drive)Bit 4SDI PositiveSafe Direction Positive activation commandYes (0 = Enable Direction Monitoring)Control (PLC -> Drive)Bit 7F_ACKFailsafe Fault Acknowledgment pulseNo (0 -> 1 Transition clears drive safety fault)Status (Drive -> PLC)Bit 0STO ActiveDrive Safe Torque Off active feedbackYes (0 = STO Active, 1 = Normal Operation)Status (Drive -> PLC)Bit 1SS1 ActiveDrive Safe Stop 1 active feedbackYes (0 = SS1 Active, 1 = Normal Operation)Status (Drive -> PLC)Bit 7Safety FaultDrive reports active internal safety faultNo (1 = Safety Fault Present)

Important: Safety signals in PROFIsafe utilize low-active fail-safe logic (de-energize to trip). A logic value of '0' commands the safe state.

Verification

Verify PROFIsafe Telegram 30 operation using the following procedure:
1. In CFC test mode, confirm that the F-channel driver F_CH_BO displays signal state '1' under healthy conditions, and the drive shows 'Safety Active / Drives Ready'.
2. Initiate an emergency stop trip condition; verify that the STO output bit drops to '0'.
3. Verify on the drive display/STARTER that Safe Torque Off triggers immediately, motor pulses are suppressed, and power to the motor windings is removed.
4. Restore the emergency stop device, issue a safety reintegration acknowledgment pulse, and confirm that the drive re-enters normal operational readiness.

Limitations and Operational Precautions

Essential safety engineering precautions:
- Failsafe signals MUST NEVER be routed through standard non-failsafe CFC blocks or non-failsafe global data blocks.
- The F_Dest_Add must be strictly unique across the entire automation network to prevent cross-talk between different physical safety devices.
- Failsafe watchdog times (F_WD_Time) must be calculated using the official Siemens SIMATIC S7 F-Execution Time and Watchdog calculator to prevent spurious passivations under peak bus load.

Engineer FAQ

Can I read the entire safety status word at once using standard SFC14 in safety CFC?

No. Standard SFC14/SFC15 cannot be called within an F-runtime group. All failsafe data exchange must route through S7 F-Systems failsafe channel blocks to maintain safety certification.

Why does CFC compiler report 'Module not configured or parameter VALUE not supplied'?

This error occurs when the I/O address assigned to the F_CH_BO block is not recognized as a failsafe address in HW Config, or when 'Create module drivers' was omitted during compilation.

Do I need the Drive ES PCS 7 library to use PROFIsafe?

No. Drive ES simplifies engineering by providing pre-assembled blocks, but PROFIsafe Telegram 30 can be engineered entirely using standard APL (FbDrive) for process control and S7 F-Systems channel blocks for safety.