Functional Safety

Functional Safety for Electronic Drive Systems:
Integrated Protection for People and Machines

Functional safety protects people, machines, and the environment from the consequences of technical malfunctions. It ensures that systems react reliably and in a controlled manner even in the event of a fault, a requirement mandated by law in many industries.

At NORD, we speak PROFINET and EtherCAT, even when it comes to safety. NORD variable frequency drives can be integrated into safety-critical applications within an existing Industrial Ethernet network via PROFIsafe or FSoE. Alternatively, stand-alone operation is also possible, for example, to implement safety-critical single-axis applications.

Result: Our comprehensive drive-based functional safety enables flexible system design without complex additional installations.

Download Flyer

Level Up Your Functional Safety with NORD

With expanded functional safety features, the NORDAC ON, for example, can now be fully integrated into demanding safety applications. Combined with proven NORD gearmotors, it creates a powerful, efficient, and consistently safe drive system configured for your application.

The safety functions STO and SS1-t (both SIL 2, PL d), as well as SS1-r, SLS, SMS, and SSM (all SIL 2, PL d), can be implemented without encoders or additional wiring.

Many safety functions are integrated directly into our variable frequency drives, often eliminating the need for an additional encoder. Our solutions can also be seamlessly integrated into existing safety communication systems through protocols such as PROFIsafe and FSoE.

Your Benefits at a Glance:

  • Compliance With Regulations: Easy implementation of functional safety with reduced drive installation
  • Scalable System Structure: Clear hierarchies and simplified cabling
  • Safety Over Ethernet: Reduced installation effort through integrated communication via standard safety protocols.
  • Direct Integration: Integration of safety-related peripherals via safe inputs and outputs.
  • Future-Proof: Seamless integration into existing networks.

Why Functional Safety Matters

Functional safety minimizes risks posed by machine functions to people, production, and the environment. It ensures that system functions are executed in a controlled manner at all times and that automatic countermeasures are implemented quickly in the event of errors.

Safety Over Ethernet Communication

In modern drive technology, communication between the frequency converter and the drive is crucial. By using secure Ethernet-based protocols, data is exchanged in real time and protected against tampering.

Depending on the control system used, specific protocols are employed:

  • PROFIsafe (for PROFInet)
  • FSoE (Fail Safe over EtherCAT)
  • CIP Safety (for EtherNet/IP)

This infrastructure significantly reduces required cabling by using existing communication channels.

Integrated Safety Functions

Our variable frequency drives offer a wide range of integrated safety functions to minimize risks to people and production.

STO

Safe Torque Off

Immediate interruption of the power supply to the drive. The motor no longer generates torque and coasts to a stop. STO is often combined with SS1 or used as a safe restart interlock.

SS1-r

Safe Stop 1

Controlled deceleration of the motor as part of the safety function. After coming to a standstill, STO is automatically activated. Corresponds to a Category 1 stop.

SS1-r is performed via controlled deceleration.

SS1-t

Safe Stop 1

Controlled deceleration of the motor as part of the safety function. After coming to a standstill, STO is automatically activated. Corresponds to a Category 1 stop.

SS1-t is time controlled.

SLS

Safe Limited Speed

Monitors a safely reduced speed, e.g., during setup mode. If the limit value is exceeded, the drive is safely shut down, usually via SS1 followed by power disconnection.

SSM

Safe Speed Monitor

Provides a safe signal indicating whether the motor speed is below a specified limit.

SMS

Safe Maximum Speed

Safe monitoring of speed, which must not exceed a maximum value. Stops the drive if it exceeds the maximum speed.

Certified Safety Levels: SIL and PL

The reliability of our systems is certified to international standards. Classification is based on potential risk in accordance with IEC 61508 (SIL) and EN ISO 13849-1 (PL).

NORD variable frequency drives with drive-based functional safety comply as standard with SIL 2 or SIL 3, as well as Performance Levels ‘d’ or ‘e’. This allows us to provide solutions for applications with the highest safety requirements.

Functional Safety in NORD Products

NORDAC ON

Integrated safety functions STO, SS1-t, SS1-r, SLS, SMS, SSM without encoder

  • Decentralized variable frequency drive for motor or wall mounting
  • Power Range: 0.50 - 3.00 hp (0.37 - 3.7 kW)
  • Safety Over Ethernet: PROFIsafe/FSoE
  • 2 safe digital inputs and 2 safe digital outputs

NORDAC ON

NORDAC LINK

Integrated safety functions STO, SS1-t

  • Decentralized variable frequency drive for wall mounting
  • Power Range: 0.50 - 10 hp (0.37 - 7.5 kW)
  • From Late 2026: SS1-r, SLS, SMS, SSM without Encoder, Safety-over-Ethernet: (PROFIsafe/FSoE)
  • 2 safe digital inputs and 2 safe digital outputs

NORDAC LINK

NORDAC PRO and FLEX

Other NORD product families, such as NORDAC PRO and NORDAC FLEX, are equipped with the integrated STO (Safe Torque Off) safety function as standard.

More About Drive Electronics

Easily Integrate Functional Safety

With Safety Over Ethernet, you can minimize risks and efficiently meet legal requirements.

You’ll find all the details and benefits summarized in our flyer.

Download Flyer Now

Application Support for Your Safety Strategy

Whether you are planning a new system or modernizing existing equipment, we support you in implementing your safety strategy in compliance with standards.

Let our application team advise you on the right solution for your industry.

Drive Electronics

NORD DRIVESYSTEMS provides intelligent electronic drive technology for demanding applications. Variable frequency drives and motor starters are available for decentralized installation or control cabinet mounting.

Our NORD Applications Team will assist you in selecting the right drive system.

Drive Electronics

NORDCON

With the NORDCON Windows app and the NORDCON mobile app, NORD provides tools for commissioning and drive optimization. Both enable easy access to electronic drive systems, simple parameter management, and comprehensive diagnostics.

Explore NORDCON

CFC Open Loop Injection Control

An innovative method enables encoderless control even in dynamic applications, providing high overload capacity and excellent dynamic performance. CFC open loop injection control can be used to regulate all NORD permanent magnet synchronous motors.

More About Encoderless Control