Bosch Rexroth HMI Integration for Safety Systems

Implementing Safety Systems with HMI Integration

Safety system control uses safety-rated PLCs and components to protect personnel and equipment from hazardous conditions. These systems implement safety functions per IEC 62443 and ISO 13849 standards with redundancy and diagnostics.

This walkthrough demonstrates practical implementation using Bosch Rexroth ctrlX WORKS / IndraWorks and HMI Integration programming.

System Requirements:

A typical Safety Systems implementation includes:

Input Devices (Sensors):
1. Emergency stop buttons (Category 0 or 1 stop): Critical for monitoring system state
2. Safety light curtains (Type 2 or Type 4): Critical for monitoring system state
3. Safety laser scanners for zone detection: Critical for monitoring system state
4. Safety interlock switches (tongue, hinged, trapped key): Critical for monitoring system state
5. Safety mats and edges: Critical for monitoring system state

Output Devices (Actuators):
1. Safety contactors (mirror contact type): Primary control output
2. Safe torque off (STO) drives: Supporting control function
3. Safety brake modules: Supporting control function
4. Lock-out valve manifolds: Supporting control function
5. Safety relay outputs: Supporting control function

Control Equipment:

• Safety PLCs (fail-safe controllers)


• Safety relays (configurable or fixed)


• Safety I/O modules with diagnostics


• Safety network protocols (PROFIsafe, CIP Safety)

1. Primary Control: Safety-rated PLC programming for personnel protection, emergency stops, and safety interlocks per IEC 61508/61511.
2. Safety Interlocks: Preventing Safety integrity level (SIL) compliance
3. Error Recovery: Handling Redundancy requirements

Implementation Steps:

Step 1: Perform hazard analysis and risk assessment

In ctrlX WORKS / IndraWorks, perform hazard analysis and risk assessment.

Step 2: Determine required safety level (SIL/PL) for each function

In ctrlX WORKS / IndraWorks, determine required safety level (sil/pl) for each function.

Step 3: Select certified safety components meeting requirements

In ctrlX WORKS / IndraWorks, select certified safety components meeting requirements.

Step 4: Design safety circuit architecture per category requirements

In ctrlX WORKS / IndraWorks, design safety circuit architecture per category requirements.

Step 5: Implement safety logic in certified safety PLC/relay

In ctrlX WORKS / IndraWorks, implement safety logic in certified safety plc/relay.

Step 6: Add diagnostics and proof test provisions

In ctrlX WORKS / IndraWorks, add diagnostics and proof test provisions.

Bosch Rexroth Function Design:

Rexroth engineers lean heavily on reusable function blocks packaged as ctrlX libraries. The mapp-technology-equivalent SDK apps expose motion-profiled FBs, recipe-driven parameter handlers, and cockpit widgets as pre-built components. OEM machine builders maintain private app catalogues for their machine families, with versioned FBs that can be swapped between machine variants without rewiring upstream code. IEC 61131-3 OOP extensions (classes, interfaces, methods) are used in more advanced teams but are optional.

Common Challenges and Solutions:

1. Achieving required safety level with practical architecture

• Solution: HMI Integration addresses this through User-friendly operation.

• Solution: HMI Integration addresses this through Real-time visualization.

• Solution: HMI Integration addresses this through Remote monitoring capability.

• Solution: HMI Integration addresses this through Alarm management.

• Use only certified safety components and PLCs


• Implement dual-channel monitoring per category requirements


• Add diagnostic coverage to detect latent faults


• Design for fail-safe operation (de-energize to trip)


• Provide regular proof testing of safety functions

• Scan Time: Optimize for 5 inputs and 4 outputs


• Memory Usage: Efficient data structures for ctrlX CORE XM21 capabilities


• Response Time: Meeting Universal requirements for Safety Systems

Bosch Rexroth Diagnostic Tools:

ctrlX WORKS Trace tool — multi-variable waveform logging at up to 1 ms sample rate,Data Layer Explorer — browse every runtime variable in a hierarchical tree with live values,Web-based diagnostics interface — device-level health, CPU and memory utilisation,IndraWorks MotionManager — axis commissioning, tuning plots, and envelope monitoring,ctrlX I/O Engineer — field-bus topology view with per-slave diagnostic status,Integrated Git history for project files with visual diff between versions,Wireshark integration for EtherCAT and Profinet frame capture and analysis,Linux journalctl access on ctrlX CORE for controller-side system log inspection,REST API query tools (Postman, curl) for runtime variable inspection during development,SSH access to the ctrlX controller for deep diagnostics when support escalation is required

Bosch Rexroth's ctrlX WORKS / IndraWorks provides tools for performance monitoring and optimization, essential for achieving the 4-8 weeks development timeline while maintaining code quality.