Schneider Electric EcoStruxure Machine Expert for Safety Systems
EcoStruxure Machine Expert (formerly SoMachine) provides Schneider Electric's unified programming environment for Modicon M221, M241, M251, M262, and M580 PLCs. Built on the CODESYS V3 platform, Machine Expert delivers IEC 61131-3 compliant programming with all five languages plus CFC (Continuous Function Chart). The environment supports object-oriented programming extensions including classes, interfaces, methods, and properties for creating sophisticated reusable code libraries....
Platform Strengths for Safety Systems:
- Excellent energy efficiency features
- Strong IoT/cloud integration
- Good balance of price and performance
- Wide product range
Unique ${brand.software} Features:
- CODESYS V3-based platform with full IEC 61131-3 language support plus extensions
- Object-oriented programming with classes, methods, properties, and interfaces
- Integrated motion control workbench for cam design and multi-axis coordination
- Machine Expert Twin for digital twin simulation and virtual commissioning
Key Capabilities:
The EcoStruxure Machine Expert environment excels at Safety Systems applications through its excellent energy efficiency features. This is particularly valuable when working with the 5 sensor types typically found in Safety Systems systems, including Safety light curtains, Emergency stop buttons, Safety door switches.
Control Equipment for Safety Systems:
- Safety PLCs (fail-safe controllers)
- Safety relays (configurable or fixed)
- Safety I/O modules with diagnostics
- Safety network protocols (PROFIsafe, CIP Safety)
Schneider Electric's controller families for Safety Systems include:
- Modicon M580: Suitable for advanced Safety Systems applications
- Modicon M340: Suitable for advanced Safety Systems applications
- Modicon M221: Suitable for advanced Safety Systems applications
- Modicon M241: Suitable for advanced Safety Systems applications
Hardware Selection Guidance:
Schneider's Modicon portfolio spans compact to high-performance controllers. M221 offers cost-effective control for simple machines. M241/M251 add performance and networking. M262 targets high-performance motion applications with Sercos III. M580 addresses process applications with hot-standby redundancy....
Industry Recognition:
High - Strong in food & beverage, water treatment, and building automation. Schneider M580/M262 controllers serve automotive with production line flexibility and energy management. Vision-guided robotics, energy monitoring via PowerLogic meters, and safety integration via Preventa controllers....
Investment Considerations:
With $$ pricing, Schneider Electric positions itself in the mid-range segment. For Safety Systems projects requiring advanced skill levels and 4-8 weeks development time, the total investment includes hardware, software licensing, training, and ongoing support.
Understanding Function Blocks for Safety Systems
Function Block Diagram (FBD) is a graphical programming language where functions and function blocks are represented as boxes connected by signal lines. Data flows from left to right through the network.
Execution Model:
Blocks execute based on data dependencies - a block executes only when all its inputs are available. Networks execute top to bottom when dependencies allow.
Core Advantages for Safety Systems:
- Visual representation of signal flow: Critical for Safety Systems when handling advanced control logic
- Good for modular programming: Critical for Safety Systems when handling advanced control logic
- Reusable components: Critical for Safety Systems when handling advanced control logic
- Excellent for process control: Critical for Safety Systems when handling advanced control logic
- Good for continuous operations: Critical for Safety Systems when handling advanced control logic
Why Function Blocks Fits Safety Systems:
Safety Systems systems in Universal typically involve:
- Sensors: Emergency stop buttons (Category 0 or 1 stop), Safety light curtains (Type 2 or Type 4), Safety laser scanners for zone detection
- Actuators: Safety contactors (mirror contact type), Safe torque off (STO) drives, Safety brake modules
- Complexity: Advanced with challenges including Achieving required safety level with practical architecture
Programming Fundamentals in Function Blocks:
StandardBlocks:
- logic: AND, OR, XOR, NOT - Boolean logic operations
- comparison: EQ, NE, LT, GT, LE, GE - Compare values
- math: ADD, SUB, MUL, DIV, MOD - Arithmetic operations
TimersCounters:
- ton: Timer On-Delay - Output turns ON after preset time
- tof: Timer Off-Delay - Output turns OFF after preset time
- tp: Pulse Timer - Output pulses for preset time
Connections:
- wires: Connect output pins to input pins to pass data
- branches: One output can connect to multiple inputs
- feedback: Outputs can feed back to inputs for state machines
Best Practices for Function Blocks:
- Arrange blocks for clear left-to-right data flow
- Use consistent spacing and alignment for readability
- Label all inputs and outputs with meaningful names
- Create custom FBs for frequently repeated logic patterns
- Minimize wire crossings by careful block placement
Common Mistakes to Avoid:
- Creating feedback loops without proper initialization
- Connecting incompatible data types
- Not considering execution order dependencies
- Overcrowding networks making them hard to read
Typical Applications:
1. HVAC control: Directly applicable to Safety Systems
2. Temperature control: Related control patterns
3. Flow control: Related control patterns
4. Batch processing: Related control patterns
Understanding these fundamentals prepares you to implement effective Function Blocks solutions for Safety Systems using Schneider Electric EcoStruxure Machine Expert.
Implementing Safety Systems with Function Blocks
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 Schneider Electric EcoStruxure Machine Expert and Function Blocks 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)
Control Strategies for Safety Systems:
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 EcoStruxure Machine Expert, perform hazard analysis and risk assessment.
Step 2: Determine required safety level (SIL/PL) for each function
In EcoStruxure Machine Expert, determine required safety level (sil/pl) for each function.
Step 3: Select certified safety components meeting requirements
In EcoStruxure Machine Expert, select certified safety components meeting requirements.
Step 4: Design safety circuit architecture per category requirements
In EcoStruxure Machine Expert, design safety circuit architecture per category requirements.
Step 5: Implement safety logic in certified safety PLC/relay
In EcoStruxure Machine Expert, implement safety logic in certified safety plc/relay.
Step 6: Add diagnostics and proof test provisions
In EcoStruxure Machine Expert, add diagnostics and proof test provisions.
Schneider Electric Function Design:
Function blocks follow object-oriented principles with Input/Output/InOut parameters, Methods extending functionality, and Properties providing controlled access. Interfaces enable polymorphism.
Common Challenges and Solutions:
1. Achieving required safety level with practical architecture
- Solution: Function Blocks addresses this through Visual representation of signal flow.
2. Managing nuisance trips while maintaining safety
- Solution: Function Blocks addresses this through Good for modular programming.
3. Integrating safety with production efficiency
- Solution: Function Blocks addresses this through Reusable components.
4. Documenting compliance with multiple standards
- Solution: Function Blocks addresses this through Excellent for process control.
Safety Considerations:
- 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
Performance Metrics:
- Scan Time: Optimize for 5 inputs and 4 outputs
- Memory Usage: Efficient data structures for Modicon M580 capabilities
- Response Time: Meeting Universal requirements for Safety Systems
Schneider Electric Diagnostic Tools:
Online monitoring overlay showing live values,Watch window tracking variables with expressions,Breakpoints pausing execution for inspection,Trace recording variable changes over time,Device diagnostics showing module status
Schneider Electric's EcoStruxure Machine Expert provides tools for performance monitoring and optimization, essential for achieving the 4-8 weeks development timeline while maintaining code quality.
Schneider Electric Function Blocks Example for Safety Systems
Complete working example demonstrating Function Blocks implementation for Safety Systems using Schneider Electric EcoStruxure Machine Expert. Follows Schneider Electric naming conventions. Tested on Modicon M580 hardware.
(* Schneider Electric EcoStruxure Machine Expert - Safety Systems Control *)
(* Reusable Function Blocks Implementation *)
(* Function blocks follow object-oriented principles with Input *)
FUNCTION_BLOCK FB_SAFETY_SYSTEMS_Controller
VAR_INPUT
bEnable : BOOL; (* Enable control *)
bReset : BOOL; (* Fault reset *)
rProcessValue : REAL; (* Emergency stop buttons (Category 0 or 1 stop) *)
rSetpoint : REAL := 100.0; (* Target value *)
bEmergencyStop : BOOL; (* Safety input *)
END_VAR
VAR_OUTPUT
rControlOutput : REAL; (* Safety contactors (mirror contact type) *)
bRunning : BOOL; (* Process active *)
bComplete : BOOL; (* Cycle complete *)
bFault : BOOL; (* Fault status *)
nFaultCode : INT; (* Diagnostic code *)
END_VAR
VAR
(* Internal Function Blocks *)
fbSafety : FB_SafetyMonitor; (* Safety logic *)
fbRamp : FB_RampGenerator; (* Soft start/stop *)
fbPID : FB_PIDController; (* Process control *)
fbDiag : FB_Diagnostics; (* Use ST_Alarm structure with bActive, bAcknowledged, dtActivation, nCode, sMessage. Array of alarms with detection, acknowledgment, and logging methods. *)
(* Internal State *)
eInternalState : E_ControlState;
tonWatchdog : TON;
END_VAR
(* Safety Monitor - Use only certified safety components and PLCs *)
fbSafety(
Enable := bEnable,
EmergencyStop := bEmergencyStop,
ProcessValue := rProcessValue,
HighLimit := rSetpoint * 1.2,
LowLimit := rSetpoint * 0.1
);
(* Main Control Logic *)
IF fbSafety.SafeToRun THEN
(* Ramp Generator - Prevents startup surge *)
fbRamp(
Enable := bEnable,
TargetValue := rSetpoint,
RampRate := 20.0, (* Universal rate *)
CurrentValue => rSetpoint
);
(* PID Controller - Process regulation *)
fbPID(
Enable := fbRamp.InPosition,
ProcessValue := rProcessValue,
Setpoint := fbRamp.CurrentValue,
Kp := 1.0,
Ki := 0.1,
Kd := 0.05,
OutputMin := 0.0,
OutputMax := 100.0
);
rControlOutput := fbPID.Output;
bRunning := TRUE;
bFault := FALSE;
nFaultCode := 0;
ELSE
(* Safe State - Implement dual-channel monitoring per category requirements *)
rControlOutput := 0.0;
bRunning := FALSE;
bFault := NOT bEnable; (* Only fault if not intentional stop *)
nFaultCode := fbSafety.FaultCode;
END_IF;
(* Diagnostics - Circular buffer with ST_LogRecord structure. Write index increments with modulo wrap. File export using SysFile library writing CSV format. *)
fbDiag(
ProcessRunning := bRunning,
FaultActive := bFault,
ProcessValue := rProcessValue,
ControlOutput := rControlOutput
);
(* Watchdog - Detects frozen control *)
tonWatchdog(IN := bRunning AND NOT fbPID.OutputChanging, PT := T#10S);
IF tonWatchdog.Q THEN
bFault := TRUE;
nFaultCode := 99; (* Watchdog fault *)
END_IF;
(* Reset Logic *)
IF bReset AND NOT bEmergencyStop THEN
bFault := FALSE;
nFaultCode := 0;
fbDiag.ClearAlarms();
END_IF;
END_FUNCTION_BLOCKCode Explanation:
- 1.Encapsulated function block follows Function blocks follow object-oriented p - reusable across Universal projects
- 2.FB_SafetyMonitor provides Use only certified safety components and PLCs including high/low limits
- 3.FB_RampGenerator prevents startup issues common in Safety Systems systems
- 4.FB_PIDController tuned for Universal: Kp=1.0, Ki=0.1
- 5.Watchdog timer detects frozen control - critical for advanced Safety Systems reliability
- 6.Diagnostic function block enables Circular buffer with ST_LogRecord structure. Write index increments with modulo wrap. File export using SysFile library writing CSV format. and Use ST_Alarm structure with bActive, bAcknowledged, dtActivation, nCode, sMessage. Array of alarms with detection, acknowledgment, and logging methods.
Best Practices
- ✓Follow Schneider Electric naming conventions: Schneider recommends Hungarian-style prefixes: g_ for globals, i_ and q_ for FB
- ✓Schneider Electric function design: Function blocks follow object-oriented principles with Input/Output/InOut parame
- ✓Data organization: Structured data uses GVLs grouping related globals and DUTs defining custom type
- ✓Function Blocks: Arrange blocks for clear left-to-right data flow
- ✓Function Blocks: Use consistent spacing and alignment for readability
- ✓Function Blocks: Label all inputs and outputs with meaningful names
- ✓Safety Systems: Keep safety logic simple and auditable
- ✓Safety Systems: Use certified function blocks from safety PLC vendor
- ✓Safety Systems: Implement cross-monitoring between channels
- ✓Debug with EcoStruxure Machine Expert: Use structured logging with severity levels
- ✓Safety: Use only certified safety components and PLCs
- ✓Use EcoStruxure Machine Expert simulation tools to test Safety Systems logic before deployment
Common Pitfalls to Avoid
- ⚠Function Blocks: Creating feedback loops without proper initialization
- ⚠Function Blocks: Connecting incompatible data types
- ⚠Function Blocks: Not considering execution order dependencies
- ⚠Schneider Electric common error: Exception 'AccessViolation': Null pointer dereference
- ⚠Safety Systems: Achieving required safety level with practical architecture
- ⚠Safety Systems: Managing nuisance trips while maintaining safety
- ⚠Neglecting to validate Emergency stop buttons (Category 0 or 1 stop) leads to control errors
- ⚠Insufficient comments make Function Blocks programs unmaintainable over time