Important safety functions now available in new servo drive series
RELATED PRODUCTS
PRODUCT INFORMATION
MANUFACTURED BY Festo
PUBLISH DATE
November 14, 2025
RELEASE DATE
November 14, 2025
CATEGORY
Motors and Drives
Festo’s CMMT-AS-S3 servo drive series adds functional safety while aiming to streamline design, wiring and certification. The CMMT-AS servo drives give OEMs a choice between two safety levels Basic (S1) and the new Advanced (S3) — allowing them to select the level that fits their application. All CMMT-AS servo drives support multiple communication protocols, including EtherNet/IP, PROFINET, EtherCAT and Modbus TCP.
Safety configuration and integration
CMMT-AS servo drives integrate safety functions within the drive, reducing reliance on external components and setup steps. OEMs can implement safety using hard-wired digital I/O or through a PROFIsafe network compatible with Siemens safety PLCs. These options allow OEMs to balance simplicity, performance, and cost requirements.
Festo’s Safety Configurator in the Festo Automation Suite is designed to help simplify setup. Users select the interface and enter the necessary parameters to enable the safety functions. A Validation Wizard expected in winter 2025 will assist with documentation by providing step-by-step prompts for verification steps and creating a safety report for certification purposes.
Safety levels for different application needs
The Basic (S1) version is intended for machines with simple requirements and limited budgets. It includes standard safety functions and uses hard-wired connections for commissioning.
Functions include:
- Safe Torque Off (STO): Removes power from the motor to prevent motion.
- Safe Brake Control (SBC): Activates the motor brake for vertical or gravity-loaded axes.
- Safe Stop 1 (SS1) Type c: Carries out a controlled stop before removing power; requires an external safety timer.
- Diagnostic outputs: Provide Safety Trip Alarm (STA) and Standby Alarm (SBA) indications.
The Advanced (S3) model is intended for machines that need additional safety functions and configuration options. It adds integrated safety features within the drive and reduces the need for external components. These features can be used with Festo EMMT-AS motors that include integrated safety encoders.
Additional functions include:
- Built-in SS1 timer: removes the need for an external timer.
- Safe Stop 2 (SS2): performs a controlled stop while maintaining servo control.
- Safe Operating Stop (SOS): monitors standstill without removing power.
- Safe Limited Speed (SLS) and Safe Maximum Speed (SMS): limit motion to defined speed thresholds for applications such as collaborative robotics or semi-automatic operations.
- Safety Over Network (PROFIsafe over PROFINET): supports managingsafety functions through a single Ethernet connection to a safety PLC.
Configuration and documentation
The new CMMT-AS includes features intended to simplify configuration. To protect certified configurations, each safety setup is password-protected through a dedicated safety-engineer login so parameters restricted and can be reviewed after validation. This feature is designed to align with requirements of the upcoming European Cyber Resilience Act (CRA).
Part of Festo's expanding safety components portfolio
The CMMT-AS servo drive series adds to Festo’s range of safety-related components, including actuators, motion systems and control software intended to support reliability and safety requirements. By incorporating additional safety functions into the drive, the series can help OEMs simplify aspects of certification, reduce wiring and address safety and performance needs in their systems.
Festo U.S.
Edited by Puja Mitra, WTWH Media, for Control Engineering
