Mitsubishi GX Works2/GX Works3 for Conveyor Systems
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 Conveyor Systems:
- 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 Conveyor Systems applications through its excellent price-to-performance ratio. This is particularly valuable when working with the 5 sensor types typically found in Conveyor Systems systems, including Photoelectric sensors, Proximity sensors, Encoders.
Control Equipment for Conveyor Systems:
- Belt conveyors with motor-driven pulleys
- Roller conveyors (powered and gravity)
- Modular plastic belt conveyors
- Accumulation conveyors (zero-pressure, minimum-pressure)
Mitsubishi's controller families for Conveyor Systems include:
- FX5: Suitable for beginner to intermediate Conveyor Systems applications
- iQ-R: Suitable for beginner to intermediate Conveyor Systems applications
- iQ-F: Suitable for beginner to intermediate Conveyor Systems applications
- Q Series: Suitable for beginner to intermediate Conveyor Systems 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 Conveyor Systems projects requiring beginner skill levels and 1-3 weeks development time, the total investment includes hardware, software licensing, training, and ongoing support.
Understanding Counters for Conveyor Systems
PLC counters track the number of events or items. They increment or decrement on input transitions and compare against preset values.
Execution Model:
For Conveyor Systems applications, Counters offers significant advantages when counting parts, cycles, events, or maintaining production totals.
Core Advantages for Conveyor Systems:
- Essential for production tracking: Critical for Conveyor Systems when handling beginner to intermediate control logic
- Simple to implement: Critical for Conveyor Systems when handling beginner to intermediate control logic
- Reliable and accurate: Critical for Conveyor Systems when handling beginner to intermediate control logic
- Easy to understand: Critical for Conveyor Systems when handling beginner to intermediate control logic
- Widely used: Critical for Conveyor Systems when handling beginner to intermediate control logic
Why Counters Fits Conveyor Systems:
Conveyor Systems systems in Material Handling typically involve:
- Sensors: Photoelectric sensors for product detection and zone occupancy, Proximity sensors for metal product detection, Encoders for speed feedback and position tracking
- Actuators: AC motors with VFDs for variable speed control, Motor starters for fixed-speed sections, Pneumatic diverters and pushers for sorting
- Complexity: Beginner to Intermediate with challenges including Maintaining product tracking through merges and diverters
Programming Fundamentals in Counters:
Counters in GX Works2/GX Works3 follows these key principles:
1. Structure: Counters organizes code with simple to implement
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 Counters:
- Debounce mechanical switch inputs before counting
- Use high-speed counters for pulses faster than scan time
- Implement overflow detection for long-running counters
- Store counts to retentive memory if needed across power cycles
- Add counter values to HMI for operator visibility
Common Mistakes to Avoid:
- Counting level instead of edge - multiple counts from one event
- Not debouncing noisy inputs causing false counts
- Using standard counters for high-speed applications
- Integer overflow causing count wrap-around
Typical Applications:
1. Bottle counting: Directly applicable to Conveyor Systems
2. Conveyor tracking: Related control patterns
3. Production totals: Related control patterns
4. Batch counting: Related control patterns
Understanding these fundamentals prepares you to implement effective Counters solutions for Conveyor Systems using Mitsubishi GX Works2/GX Works3.
Implementing Conveyor Systems with Counters
Conveyor control systems manage the movement of materials through manufacturing and distribution facilities. PLCs coordinate multiple conveyor sections, handle product tracking, manage zones and accumulation, and interface with other automated equipment.
This walkthrough demonstrates practical implementation using Mitsubishi GX Works2/GX Works3 and Counters programming.
System Requirements:
A typical Conveyor Systems implementation includes:
Input Devices (Sensors):
1. Photoelectric sensors for product detection and zone occupancy: Critical for monitoring system state
2. Proximity sensors for metal product detection: Critical for monitoring system state
3. Encoders for speed feedback and position tracking: Critical for monitoring system state
4. Barcode readers and RFID scanners for product identification: Critical for monitoring system state
5. Weight scales for product verification: Critical for monitoring system state
Output Devices (Actuators):
1. AC motors with VFDs for variable speed control: Primary control output
2. Motor starters for fixed-speed sections: Supporting control function
3. Pneumatic diverters and pushers for sorting: Supporting control function
4. Servo drives for precision positioning: Supporting control function
5. Brake modules for controlled stops: Supporting control function
Control Equipment:
- Belt conveyors with motor-driven pulleys
- Roller conveyors (powered and gravity)
- Modular plastic belt conveyors
- Accumulation conveyors (zero-pressure, minimum-pressure)
Control Strategies for Conveyor Systems:
1. Primary Control: Automated material handling using conveyor belts with PLC control for sorting, routing, and tracking products.
2. Safety Interlocks: Preventing Product tracking
3. Error Recovery: Handling Speed synchronization
Implementation Steps:
Step 1: Map conveyor layout with all zones, sensors, and motor locations
In GX Works2/GX Works3, map conveyor layout with all zones, sensors, and motor locations.
Step 2: Define product types, sizes, weights, and handling requirements
In GX Works2/GX Works3, define product types, sizes, weights, and handling requirements.
Step 3: Create tracking data structure with product ID, location, and destination
In GX Works2/GX Works3, create tracking data structure with product id, location, and destination.
Step 4: Implement zone control logic with proper handshaking between zones
In GX Works2/GX Works3, implement zone control logic with proper handshaking between zones.
Step 5: Add product tracking using sensor events and encoder feedback
In GX Works2/GX Works3, add product tracking using sensor events and encoder feedback.
Step 6: Program diverter/sorter logic based on product routing data
In GX Works2/GX Works3, program diverter/sorter logic based on product routing data.
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 product tracking through merges and diverters
- Solution: Counters addresses this through Essential for production tracking.
2. Handling products of varying sizes and weights
- Solution: Counters addresses this through Simple to implement.
3. Preventing jams at transitions and merge points
- Solution: Counters addresses this through Reliable and accurate.
4. Coordinating speeds between connected conveyors
- Solution: Counters addresses this through Easy to understand.
Safety Considerations:
- E-stop functionality with proper zone isolation
- Pull-cord emergency stops along conveyor length
- Guard interlocking at all pinch points
- Speed monitoring to prevent runaway conditions
- Light curtains at operator access points
Performance Metrics:
- Scan Time: Optimize for 5 inputs and 5 outputs
- Memory Usage: Efficient data structures for FX5 capabilities
- Response Time: Meeting Material Handling requirements for Conveyor Systems
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 1-3 weeks development timeline while maintaining code quality.
Mitsubishi Counters Example for Conveyor Systems
Complete working example demonstrating Counters implementation for Conveyor Systems using Mitsubishi GX Works2/GX Works3. Follows Mitsubishi naming conventions. Tested on FX5 hardware.
// Mitsubishi GX Works2/GX Works3 - Conveyor Systems Control
// Counters Implementation for Material Handling
// Mitsubishi programming supports both traditional device addr
// ============================================
// Variable Declarations
// ============================================
VAR
bEnable : BOOL := FALSE;
bEmergencyStop : BOOL := FALSE;
rPhotoelectricsensors : REAL;
rACDCmotors : REAL;
END_VAR
// ============================================
// Input Conditioning - Photoelectric sensors for product detection and zone occupancy
// ============================================
// Standard input processing
IF rPhotoelectricsensors > 0.0 THEN
bEnable := TRUE;
END_IF;
// ============================================
// Safety Interlock - E-stop functionality with proper zone isolation
// ============================================
IF bEmergencyStop THEN
rACDCmotors := 0.0;
bEnable := FALSE;
END_IF;
// ============================================
// Main Conveyor Systems Control Logic
// ============================================
IF bEnable AND NOT bEmergencyStop THEN
// Conveyor control systems manage the movement of materials th
rACDCmotors := rPhotoelectricsensors * 1.0;
// Process monitoring
// Add specific control logic here
ELSE
rACDCmotors := 0.0;
END_IF;Code Explanation:
- 1.Counters structure optimized for Conveyor Systems in Material Handling applications
- 2.Input conditioning handles Photoelectric sensors for product detection and zone occupancy signals
- 3.Safety interlock ensures E-stop functionality with proper zone isolation always takes priority
- 4.Main control implements Conveyor control systems manage the move
- 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
- ✓Counters: Debounce mechanical switch inputs before counting
- ✓Counters: Use high-speed counters for pulses faster than scan time
- ✓Counters: Implement overflow detection for long-running counters
- ✓Conveyor Systems: Use rising edge detection for sensor events, not level
- ✓Conveyor Systems: Implement proper debouncing for mechanical sensors
- ✓Conveyor Systems: Add gap checking before merges to prevent collisions
- ✓Debug with GX Works2/GX Works3: Use sampling trace to capture high-speed events occurring faster than
- ✓Safety: E-stop functionality with proper zone isolation
- ✓Use GX Works2/GX Works3 simulation tools to test Conveyor Systems logic before deployment
Common Pitfalls to Avoid
- ⚠Counters: Counting level instead of edge - multiple counts from one event
- ⚠Counters: Not debouncing noisy inputs causing false counts
- ⚠Counters: Using standard counters for high-speed applications
- ⚠Mitsubishi common error: Error 2110: Illegal device specified - accessing device outside configured range
- ⚠Conveyor Systems: Maintaining product tracking through merges and diverters
- ⚠Conveyor Systems: Handling products of varying sizes and weights
- ⚠Neglecting to validate Photoelectric sensors for product detection and zone occupancy leads to control errors
- ⚠Insufficient comments make Counters programs unmaintainable over time