Allen‑Bradley 20‑750‑S PowerFlex 750 Safe Torque Off (STO) Option Module

Hardware‑based Safe Torque Off option module for PowerFlex 750‑Series drives, certified for SIL3 and PLe safety applications. Provides dedicated torque removal for motor coast‑to‑stop without disconnecting main drive power, eliminating line contactors and reducing panel space.

Applications

• Robotic work cells and automated assembly lines

• Web handling (printing, converting, unwinds/rewinds)

• Heavy material transport (cranes, hoists, conveyors)

• High‑risk industrial machinery requiring SIL3 / PLe compliance

• Packaging machinery with frequent safety interventions

Key Features

• Hardwired Safe Torque Off (STO) with redundant 24V DC safety inputs

• Certified SIL3 (IEC 61508, IEC 61800‑5‑2), PLe (ISO 13849‑1), Category 4

• Drive stays energized while motor is torque‑free – eliminates bulky line contactors

• Fits internal option slot of PowerFlex 753 and PowerFlex 755 drives (all frames)

• Response time < 12 ms typical

• Pluggable terminal blocks for fast wiring and replacement

• Rapid restart: drive logic remains powered, resume operation immediately after safety circuit clears

Technical Specifications

• Manufacturer: Allen‑Bradley / Rockwell Automation

• Model: 20‑750‑S

• Series: PowerFlex 750‑Series Options

• Safety function: Hardwired Safe Torque Off (STO) – stop category 0 (coast‑to‑stop)

• Safety ratings: SIL3 (IEC 61508, IEC 61800‑5‑2), PLe (ISO 13849‑1), Category 4

• Input voltage: 24V DC ± 10% (user‑supplied)

• Safety inputs: Redundant 24V DC (Safety Power + Safety Enable)

• Compatibility: PowerFlex 753, PowerFlex 755 (all frame sizes)

• Mounting: Dedicated internal option slot (snap‑in)

• Response time: < 12 ms (typical)

• Weight: 0.13 kg (0.28 lb)

• Certifications: TÜV Rheinland, CE, RoHS

System Integration

• Drives: PowerFlex 753, PowerFlex 755, PowerFlex 755TL, PowerFlex 755TR, PowerFlex 755TM drive systems

• Safety Controllers: GuardLogix 5570/5580 with CIP Safety (requires 20‑750‑S3/S4 for networked safety)

• External Safety Relay: Guardmaster Minotaur MSR127TP (external relay required for Safe Stop 1 deceleration ramp)

• Software: Studio 5000 Logix Designer, DriveExecutive

• Note: For networked safety (CIP Safety), use 20‑750‑S3 (Integrated Safety) or 20‑750‑S4 (Integrated Safety Functions).

Related Products

• Drive Pairing: PowerFlex 753 / PowerFlex 755 AC Drive – system core

• Networked Safety Alternative: 20‑750‑S3 Integrated Safety Option – CIP Safety over EtherNet/IP

• Advanced Safety Monitor: 20‑750‑S1 Safe Speed Monitor – adds SS1, SLS, SSR, SDI safety functions

• External Safety Relay: Guardmaster Minotaur MSR127TP – timed deceleration ramp for SS1

PLC ERA is an independent industrial automation distributor. Products are sourced from established supply channels and inspected before shipment. International shipping available.