Mitsubishi GX Works2/GX Works3 for Material Handling
GX Works3 represents Mitsubishi's latest engineering software supporting the MELSEC iQ-R and iQ-F series controllers, while GX Works2 remains in use for legacy Q, L, and FX5 series PLCs. The programming environment features a project-based structure organizing programs into multiple POUs (Program Organization Units) including main programs, function blocks, and structured projects. Unlike Western PLC manufacturers, Mitsubishi supports both device-addressed programming (X0, Y0, M0, D0) and label-...
Platform Strengths for Material Handling:
- Excellent price-to-performance ratio
- Fast processing speeds
- Compact form factors
- Strong support in Asia-Pacific
Unique ${brand.software} Features:
- Simple Motion module integration with motion SFC (Sequential Function Chart) programming eliminating complex positioning code
- RD.DPR instruction providing direct device programming without software transfer for recipe adjustments
- Melsoft Navigator project management integrating multiple controllers, HMIs, and network devices in unified environment
- Multiple CPU configuration allowing up to 4 CPUs in single rack sharing memory via high-speed backplane
Key Capabilities:
The GX Works2/GX Works3 environment excels at Material Handling applications through its excellent price-to-performance ratio. This is particularly valuable when working with the 5 sensor types typically found in Material Handling systems, including Laser scanners, RFID readers, Barcode scanners.
Control Equipment for Material Handling:
- Automated storage and retrieval systems (AS/RS)
- Automated guided vehicles (AGVs/AMRs)
- Vertical lift modules (VLMs)
- Carousel systems (horizontal and vertical)
Mitsubishi's controller families for Material Handling include:
- FX5: Suitable for intermediate to advanced Material Handling applications
- iQ-R: Suitable for intermediate to advanced Material Handling applications
- iQ-F: Suitable for intermediate to advanced Material Handling applications
- Q Series: Suitable for intermediate to advanced Material Handling applications
Hardware Selection Guidance:
Mitsubishi offers several controller families addressing different performance and application requirements. The MELSEC iQ-R series represents the flagship product line with processing speeds as fast as 0.98ns per basic instruction supporting applications from small machines to complex automated systems. R04CPU provides 40K steps program capacity and 256K words data memory suitable for compact mac...
Industry Recognition:
High - Popular in electronics manufacturing, packaging, and assembly. Mitsubishi PLCs serve Japanese and Asian automotive manufacturers with MELSEC iQ-R controllers managing assembly line transfers, welding automation, and quality inspection systems. Body assembly lines use multiple CPU configurations (up to 4 CPUs in single rack) distributing control: CPU1 handles co...
Investment Considerations:
With $$ pricing, Mitsubishi positions itself in the mid-range segment. For Material Handling projects requiring advanced skill levels and 4-12 weeks development time, the total investment includes hardware, software licensing, training, and ongoing support.
Understanding Timers for Material Handling
PLC timers measure elapsed time to implement delays, pulses, and timed operations. They use accumulated time compared against preset values to control outputs.
Execution Model:
For Material Handling applications, Timers offers significant advantages when any application requiring time delays, time-based sequencing, or time monitoring.
Core Advantages for Material Handling:
- Simple to implement: Critical for Material Handling when handling intermediate to advanced control logic
- Highly reliable: Critical for Material Handling when handling intermediate to advanced control logic
- Essential for most applications: Critical for Material Handling when handling intermediate to advanced control logic
- Easy to troubleshoot: Critical for Material Handling when handling intermediate to advanced control logic
- Widely supported: Critical for Material Handling when handling intermediate to advanced control logic
Why Timers Fits Material Handling:
Material Handling systems in Logistics & Warehousing typically involve:
- Sensors: Barcode scanners for product/location identification, RFID readers for pallet and container tracking, Photoelectric sensors for load presence detection
- Actuators: Conveyor motors and drives, Crane bridge, hoist, and trolley drives, Shuttle car drives
- Complexity: Intermediate to Advanced with challenges including Maintaining inventory accuracy in real-time
Programming Fundamentals in Timers:
Timers in GX Works2/GX Works3 follows these key principles:
1. Structure: Timers organizes code with highly reliable
2. Execution: Scan cycle integration ensures 5 sensor inputs are processed reliably
3. Data Handling: Proper data types for 5 actuator control signals
Best Practices for Timers:
- Use constants or parameters for preset times - avoid hardcoded values
- Add timer status to HMI for operator visibility
- Implement timeout timers for fault detection in sequences
- Use appropriate timer resolution for the application
- Document expected timer values in comments
Common Mistakes to Avoid:
- Using TON when TOF behavior is needed or vice versa
- Not resetting RTO timers, causing unexpected timeout
- Timer preset too short relative to scan time causing missed timing
- Using software timers for safety-critical timing
Typical Applications:
1. Motor start delays: Directly applicable to Material Handling
2. Alarm delays: Related control patterns
3. Process timing: Related control patterns
4. Conveyor sequencing: Related control patterns
Understanding these fundamentals prepares you to implement effective Timers solutions for Material Handling using Mitsubishi GX Works2/GX Works3.
Implementing Material Handling with Timers
Material handling automation uses PLCs to control the movement, storage, and retrieval of materials in warehouses, distribution centers, and manufacturing facilities. These systems optimize storage density, picking efficiency, and inventory accuracy.
This walkthrough demonstrates practical implementation using Mitsubishi GX Works2/GX Works3 and Timers programming.
System Requirements:
A typical Material Handling implementation includes:
Input Devices (Sensors):
1. Barcode scanners for product/location identification: Critical for monitoring system state
2. RFID readers for pallet and container tracking: Critical for monitoring system state
3. Photoelectric sensors for load presence detection: Critical for monitoring system state
4. Height and dimension sensors for load verification: Critical for monitoring system state
5. Position encoders for crane and shuttle systems: Critical for monitoring system state
Output Devices (Actuators):
1. Conveyor motors and drives: Primary control output
2. Crane bridge, hoist, and trolley drives: Supporting control function
3. Shuttle car drives: Supporting control function
4. Fork positioning and load handling: Supporting control function
5. Vertical lift mechanisms: Supporting control function
Control Equipment:
- Automated storage and retrieval systems (AS/RS)
- Automated guided vehicles (AGVs/AMRs)
- Vertical lift modules (VLMs)
- Carousel systems (horizontal and vertical)
Control Strategies for Material Handling:
1. Primary Control: Automated material movement using PLCs for warehouse automation, AGVs, and logistics systems.
2. Safety Interlocks: Preventing Route optimization
3. Error Recovery: Handling Traffic management
Implementation Steps:
Step 1: Map all storage locations with addressing scheme
In GX Works2/GX Works3, map all storage locations with addressing scheme.
Step 2: Define product characteristics (size, weight, handling requirements)
In GX Works2/GX Works3, define product characteristics (size, weight, handling requirements).
Step 3: Implement location tracking database interface
In GX Works2/GX Works3, implement location tracking database interface.
Step 4: Program crane/shuttle motion control with positioning
In GX Works2/GX Works3, program crane/shuttle motion control with positioning.
Step 5: Add load verification (presence, dimension, weight)
In GX Works2/GX Works3, add load verification (presence, dimension, weight).
Step 6: Implement WMS interface for task assignment
In GX Works2/GX Works3, implement wms interface for task assignment.
Mitsubishi Function Design:
Function block (FB) programming in Mitsubishi creates reusable logic modules with defined interfaces encapsulating complexity. FB definition includes input variables (VAR_INPUT), output variables (VAR_OUTPUT), internal variables (VAR), and retained variables (VAR_RETAIN) maintaining values between calls. Creating motor control FB: inputs include Start_Cmd (BOOL), Stop_Cmd (BOOL), Speed_SP (INT), outputs include Running_Sts (BOOL), Fault_Sts (BOOL), Actual_Speed (INT), internal variables store timers, state machine stages, and diagnostic counters. FB instantiation creates instance: Motor1 (Motor_FB) with unique variable storage, allowing multiple instances Motor1, Motor2, Motor3 controlling different motors using same logic. Array of FB instances: Motors : ARRAY[1..10] OF Motor_FB accessed as Motors[3].Running_Sts checking status of motor 3. Standard function (FUN) differs from FB by lacking internal memory, suitable for calculations or conversions: Temp_Conversion_FUN(Celsius) returns Fahrenheit without retaining historical data. Structured text programming within FBs/FUNs provides clearer logic for complex algorithms compared to ladder: IF-THEN-ELSIF-ELSE structures, FOR loops, CASE statements expressing intent more directly than ladder equivalents. EN/ENO functionality enables conditional execution: EN (enable input) controls whether FB executes, ENO (enable output) indicates successful execution detecting errors within block. Library management exports FBs to library files (.glib) shared across projects and engineering teams, versioned to track modifications and ensure consistency. The intelligent function module (IFM) templates provide pre-built FBs for common applications: PID control, analog scaling, motion positioning reducing development time and providing tested reliable code. Simulation mode tests FB logic without hardware, allowing desktop development and unit testing before commissioning. Protection functionality encrypts FB contents preventing unauthorized viewing or modification, useful for proprietary algorithms or OEM machine builders distributing programs to end users.
Common Challenges and Solutions:
1. Maintaining inventory accuracy in real-time
- Solution: Timers addresses this through Simple to implement.
2. Handling damaged or misplaced loads
- Solution: Timers addresses this through Highly reliable.
3. Coordinating multiple cranes in same aisle
- Solution: Timers addresses this through Essential for most applications.
4. Optimizing storage assignment dynamically
- Solution: Timers addresses this through Easy to troubleshoot.
Safety Considerations:
- Aisle entry protection with light curtains and interlocks
- Personnel detection in automated zones
- Safe positioning for maintenance access
- Overload protection for cranes and lifts
- Fire suppression system integration
Performance Metrics:
- Scan Time: Optimize for 5 inputs and 5 outputs
- Memory Usage: Efficient data structures for FX5 capabilities
- Response Time: Meeting Logistics & Warehousing requirements for Material Handling
Mitsubishi Diagnostic Tools:
Device memory monitor: Real-time table displaying current values for X, Y, M, D devices with force capability,Entry data monitor: Shows actual rung logic states with contact ON/OFF indication during program execution,Device test: Manually control outputs and set internal relays for wiring verification without program influence,Intelligent module diagnostics: Buffer memory display showing module status, error codes, and configuration,Scan time monitor: Displays current, maximum, and minimum scan times identifying performance issues,Error code history: Chronological log of system errors, module faults, and CPU events with timestamps,CC-Link/network diagnostics: Visual network status showing connected stations, errors, and communication statistics,SD card operation log: Records all SD card read/write operations, file transfers, and access timestamps,Remote diagnosis via Ethernet: Connect GX Works over network for monitoring and troubleshooting without local access,Sampling trace: Records device value changes over time with trigger conditions for intermittent fault analysis,System monitor: Displays CPU load, memory usage, and battery status for predictive maintenance,Safety diagnosis (safety CPU): Dedicated diagnostics for safety I/O discrepancy detection and emergency stop chain status
Mitsubishi's GX Works2/GX Works3 provides tools for performance monitoring and optimization, essential for achieving the 4-12 weeks development timeline while maintaining code quality.
Mitsubishi Timers Example for Material Handling
Complete working example demonstrating Timers implementation for Material Handling using Mitsubishi GX Works2/GX Works3. Follows Mitsubishi naming conventions. Tested on FX5 hardware.
// Mitsubishi GX Works2/GX Works3 - Material Handling Control
// Timers Implementation for Logistics & Warehousing
// Mitsubishi programming supports both traditional device addr
// ============================================
// Variable Declarations
// ============================================
VAR
bEnable : BOOL := FALSE;
bEmergencyStop : BOOL := FALSE;
rLaserscanners : REAL;
rAGVmotors : REAL;
END_VAR
// ============================================
// Input Conditioning - Barcode scanners for product/location identification
// ============================================
// Standard input processing
IF rLaserscanners > 0.0 THEN
bEnable := TRUE;
END_IF;
// ============================================
// Safety Interlock - Aisle entry protection with light curtains and interlocks
// ============================================
IF bEmergencyStop THEN
rAGVmotors := 0.0;
bEnable := FALSE;
END_IF;
// ============================================
// Main Material Handling Control Logic
// ============================================
IF bEnable AND NOT bEmergencyStop THEN
// Material handling automation uses PLCs to control the moveme
rAGVmotors := rLaserscanners * 1.0;
// Process monitoring
// Add specific control logic here
ELSE
rAGVmotors := 0.0;
END_IF;Code Explanation:
- 1.Timers structure optimized for Material Handling in Logistics & Warehousing applications
- 2.Input conditioning handles Barcode scanners for product/location identification signals
- 3.Safety interlock ensures Aisle entry protection with light curtains and interlocks always takes priority
- 4.Main control implements Material handling automation uses PLCs t
- 5.Code runs every scan cycle on FX5 (typically 5-20ms)
Best Practices
- ✓Follow Mitsubishi naming conventions: Mitsubishi programming supports both traditional device addressing (M0, D100, X1
- ✓Mitsubishi function design: Function block (FB) programming in Mitsubishi creates reusable logic modules wit
- ✓Data organization: Mitsubishi uses file registers (R devices) and structured data in function block
- ✓Timers: Use constants or parameters for preset times - avoid hardcoded values
- ✓Timers: Add timer status to HMI for operator visibility
- ✓Timers: Implement timeout timers for fault detection in sequences
- ✓Material Handling: Verify load presence before and after each move
- ✓Material Handling: Implement inventory checkpoints for reconciliation
- ✓Material Handling: Use location states to prevent double storage
- ✓Debug with GX Works2/GX Works3: Use sampling trace to capture high-speed events occurring faster than
- ✓Safety: Aisle entry protection with light curtains and interlocks
- ✓Use GX Works2/GX Works3 simulation tools to test Material Handling logic before deployment
Common Pitfalls to Avoid
- ⚠Timers: Using TON when TOF behavior is needed or vice versa
- ⚠Timers: Not resetting RTO timers, causing unexpected timeout
- ⚠Timers: Timer preset too short relative to scan time causing missed timing
- ⚠Mitsubishi common error: Error 2110: Illegal device specified - accessing device outside configured range
- ⚠Material Handling: Maintaining inventory accuracy in real-time
- ⚠Material Handling: Handling damaged or misplaced loads
- ⚠Neglecting to validate Barcode scanners for product/location identification leads to control errors
- ⚠Insufficient comments make Timers programs unmaintainable over time