⚙️ Why Parker Integrates Safe Torque Off (STO) in AC15, AC20, and AC30 Inverters
Have you ever wondered why Parker integrates the Safe Torque Off (STO) function into the latest generation of drives such as AC15, AC20, and AC30? This is not just a technical upgrade — it’s a major step forward to enhance safety, reduce costs, and optimize performance in modern industrial automation.
🔍 What Is STO and Why Is It Important?
Safe Torque Off (STO) is a safety function built directly into the drive, allowing the motor torque to be instantly disabled without disconnecting the main power supply. Once activated, the motor stops completely, eliminating the risk of unintentional restart — while the control circuitry remains powered, making system restart and network communication quick and easy.
In today’s automated production lines, especially those involving high-speed rotary motion, operator and equipment safety is always a top priority. In the past, safety systems relied on complex mechanical contactors and relays that were costly and prone to wear. The integrated STO function is the perfect replacement.
📜 Certified Safety Standards
- AC20: Independently certified to EN ISO13849-1:2015, EN61800-5-2:2017, and EN61508, achieving SIL2 / PL d.
- AC30: Certified to EN ISO13849-1 at PLe Category 3 or SIL3 according to EN61800-5-2, fully compliant with the European Machinery Directive.
Depending on your project’s safety requirements, you can choose AC20 or AC30 to achieve the appropriate safety level.
💡 Benefits of STO Integration in Parker Drives
- 🛡️ Maximum safety: Prevents accidental motor start during maintenance or emergency stops.
- ✅ Global compliance: AC20 certified for SIL2 / PL d; AC30 for SIL3 / PL e – the highest safety level.
- 💰 Cost-effective: Eliminates the need for external safety contactors or relays.
- ⚙️ Simplified wiring: Compact system design for easier installation and maintenance.
- 🔧 Reduced wear: Avoids frequent main power switching, extending contactor lifespan.
- ⚡ Instant response: Torque is cut immediately upon safety signal activation.
- 🔄 Continuous operation: Enables local maintenance without halting the entire production line.
🏭 Parker Drives with Integrated STO & Precision Torque Control
Kỹ Thuật Việt (Parker Drives Vietnam) supplies the full range of Parker variable speed drives equipped with certified STO safety features. All models also support accurate Torque Control for demanding industrial applications:
- ⚙️ Parker AC15 – Compact and efficient for standard automation tasks.
- ⚙️ Parker AC20 – Flexible and easy to configure, certified to SIL2 / PL d.
- ⚙️ Parker AC30 – Modular architecture with powerful communication, certified SIL3 / PL e.
- ⚙️ Parker DC590P – High-performance DC drive with torque control accuracy up to ±0.1%.
Each model features dual independent STO channels, meeting the highest factory safety standards while maintaining outstanding performance.
🏁 Conclusion
Integrating Safe Torque Off (STO) into Parker drives is more than a technical improvement — it’s a commitment to safety, efficiency, and cost optimization. STO provides a complete and reliable solution for modern industrial automation systems.
Kỹ Thuật Việt proudly supports businesses with consultation, supply, installation, and commissioning of Parker AC & DC drives that meet international safety standards — ensuring long-term reliability, precision, and performance.
