Mitsubishi GX Works2/GX Works3 for Packaging Automation
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 Packaging Automation:
- 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 Packaging Automation applications through its excellent price-to-performance ratio. This is particularly valuable when working with the 5 sensor types typically found in Packaging Automation systems, including Vision systems, Weight sensors, Barcode scanners.
Control Equipment for Packaging Automation:
- Form-fill-seal machines (horizontal and vertical)
- Case erectors and sealers
- Labeling systems (pressure sensitive, shrink sleeve)
- Case packers (drop, wrap-around, robotic)
Mitsubishi's controller families for Packaging Automation include:
- FX5: Suitable for intermediate to advanced Packaging Automation applications
- iQ-R: Suitable for intermediate to advanced Packaging Automation applications
- iQ-F: Suitable for intermediate to advanced Packaging Automation applications
- Q Series: Suitable for intermediate to advanced Packaging Automation 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. Packaging machinery manufacturers across Asia Pacific standardize on Mitsubishi for flexibility, compact form factors, and responsive local technical support. Form-fill-seal machines use coordinated motion controlling film advance, product dosing, sealing, and cutting with electronic line shaft (vir...
Investment Considerations:
With $$ pricing, Mitsubishi positions itself in the mid-range segment. For Packaging Automation projects requiring advanced skill levels and 3-6 weeks development time, the total investment includes hardware, software licensing, training, and ongoing support.
Understanding Ladder Logic for Packaging Automation
Ladder Logic (LAD) is a graphical programming language that represents control circuits as rungs on a ladder. It was designed to mimic the appearance of relay logic diagrams, making it intuitive for electricians and maintenance technicians familiar with hardwired control systems.
Execution Model:
Programs execute from left to right, top to bottom. Each rung is evaluated during the PLC scan cycle, with input conditions on the left determining whether output coils on the right are energized.
Core Advantages for Packaging Automation:
- Highly visual and intuitive: Critical for Packaging Automation when handling intermediate to advanced control logic
- Easy to troubleshoot: Critical for Packaging Automation when handling intermediate to advanced control logic
- Industry standard: Critical for Packaging Automation when handling intermediate to advanced control logic
- Minimal programming background required: Critical for Packaging Automation when handling intermediate to advanced control logic
- Easy to read and understand: Critical for Packaging Automation when handling intermediate to advanced control logic
Why Ladder Logic Fits Packaging Automation:
Packaging Automation systems in Packaging typically involve:
- Sensors: Product detection sensors for counting and positioning, Registration sensors for label and film alignment, Barcode/2D code readers for verification
- Actuators: Servo drives for precise motion control, Pneumatic cylinders for pick-and-place, Vacuum generators and cups
- Complexity: Intermediate to Advanced with challenges including Maintaining registration at high speeds
Programming Fundamentals in Ladder Logic:
Contacts:
- xic: Examine If Closed (XIC) - Normally Open contact that passes power when the associated bit is TRUE/1
- xio: Examine If Open (XIO) - Normally Closed contact that passes power when the associated bit is FALSE/0
- risingEdge: One-Shot Rising (OSR) - Passes power for one scan when input transitions from FALSE to TRUE
Coils:
- ote: Output Energize (OTE) - Standard output coil, energized when rung conditions are true
- otl: Output Latch (OTL) - Latching coil that remains ON until explicitly unlatched
- otu: Output Unlatch (OTU) - Unlatch coil that turns off a latched output
Branches:
- parallel: OR logic - Multiple paths allow current flow if ANY path is complete
- series: AND logic - All contacts in series must be closed for current flow
- nested: Complex logic combining parallel and series branches
Best Practices for Ladder Logic:
- Keep rungs simple - split complex logic into multiple rungs for clarity
- Use descriptive tag names that indicate function (e.g., Motor_Forward_CMD not M001)
- Place most restrictive conditions first (leftmost) for faster evaluation
- Group related rungs together with comment headers
- Use XIO contacts for safety interlocks at the start of output rungs
Common Mistakes to Avoid:
- Using the same OTE coil in multiple rungs (causes unpredictable behavior)
- Forgetting to include stop conditions in seal-in circuits
- Not using one-shots for counter inputs, causing multiple counts per event
- Placing outputs before all conditions are evaluated
Typical Applications:
1. Start/stop motor control: Directly applicable to Packaging Automation
2. Conveyor systems: Related control patterns
3. Assembly lines: Related control patterns
4. Traffic lights: Related control patterns
Understanding these fundamentals prepares you to implement effective Ladder Logic solutions for Packaging Automation using Mitsubishi GX Works2/GX Works3.
Implementing Packaging Automation with Ladder Logic
Packaging automation systems use PLCs to coordinate primary, secondary, and tertiary packaging operations. These systems control filling, labeling, case packing, palletizing, and integration with production and warehouse systems.
This walkthrough demonstrates practical implementation using Mitsubishi GX Works2/GX Works3 and Ladder Logic programming.
System Requirements:
A typical Packaging Automation implementation includes:
Input Devices (Sensors):
1. Product detection sensors for counting and positioning: Critical for monitoring system state
2. Registration sensors for label and film alignment: Critical for monitoring system state
3. Barcode/2D code readers for verification: Critical for monitoring system state
4. Vision systems for quality inspection: Critical for monitoring system state
5. Reject confirmation sensors: Critical for monitoring system state
Output Devices (Actuators):
1. Servo drives for precise motion control: Primary control output
2. Pneumatic cylinders for pick-and-place: Supporting control function
3. Vacuum generators and cups: Supporting control function
4. Glue and tape applicators: Supporting control function
5. Film tensioners and seal bars: Supporting control function
Control Equipment:
- Form-fill-seal machines (horizontal and vertical)
- Case erectors and sealers
- Labeling systems (pressure sensitive, shrink sleeve)
- Case packers (drop, wrap-around, robotic)
Control Strategies for Packaging Automation:
1. Primary Control: Automated packaging systems using PLCs for product wrapping, boxing, labeling, and palletizing.
2. Safety Interlocks: Preventing Product changeover
3. Error Recovery: Handling High-speed synchronization
Implementation Steps:
Step 1: Define packaging specifications for all product variants
In GX Works2/GX Works3, define packaging specifications for all product variants.
Step 2: Create motion profiles for each packaging format
In GX Works2/GX Works3, create motion profiles for each packaging format.
Step 3: Implement registration control with encoder feedback
In GX Works2/GX Works3, implement registration control with encoder feedback.
Step 4: Program pattern generation for case and pallet loading
In GX Works2/GX Works3, program pattern generation for case and pallet loading.
Step 5: Add reject handling with confirmation logic
In GX Works2/GX Works3, add reject handling with confirmation logic.
Step 6: Implement barcode/vision integration for verification
In GX Works2/GX Works3, implement barcode/vision integration for verification.
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 registration at high speeds
- Solution: Ladder Logic addresses this through Highly visual and intuitive.
2. Handling product variability in automated systems
- Solution: Ladder Logic addresses this through Easy to troubleshoot.
3. Quick changeover between package formats
- Solution: Ladder Logic addresses this through Industry standard.
4. Synchronizing multiple machines in a line
- Solution: Ladder Logic addresses this through Minimal programming background required.
Safety Considerations:
- Guarding around rotating and reciprocating parts
- Safety-rated position monitoring for setup access
- Heat hazard protection for seal bars and shrink tunnels
- Proper pinch point guarding
- Robot safety zones and light curtains
Performance Metrics:
- Scan Time: Optimize for 5 inputs and 5 outputs
- Memory Usage: Efficient data structures for FX5 capabilities
- Response Time: Meeting Packaging requirements for Packaging Automation
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 3-6 weeks development timeline while maintaining code quality.
Mitsubishi Ladder Logic Example for Packaging Automation
Complete working example demonstrating Ladder Logic implementation for Packaging Automation using Mitsubishi GX Works2/GX Works3. Follows Mitsubishi naming conventions. Tested on FX5 hardware.
// Mitsubishi GX Works2/GX Works3 - Packaging Automation Control
// Ladder Logic Implementation
// Naming: Mitsubishi programming supports both traditional device addr...
NETWORK 1: Input Conditioning - Product detection sensors for counting and positioning
|----[ Vision_systems ]----[TON Timer_Debounce]----( Enable )
|
| Timer: On-Delay, PT: 500ms (debounce for Packaging environment)
NETWORK 2: Safety Interlock Chain - Emergency stop priority
|----[ Enable ]----[ NOT E_Stop ]----[ Guards_OK ]----+----( Safe_To_Run )
| |
|----[ Fault_Active ]------------------------------------------+----( Alarm_Horn )
NETWORK 3: Main Packaging Automation Control
|----[ Safe_To_Run ]----[ Weight_senso ]----+----( Servo_motors )
| |
|----[ Manual_Override ]----------------------------+
NETWORK 4: Sequence Control - State machine
|----[ Motor_Run ]----[CTU Cycle_Counter]----( Batch_Complete )
|
| Counter: PV := 50 (Packaging batch size)
NETWORK 5: Output Control with Feedback
|----[ Servo_motors ]----[TON Feedback_Timer]----[ NOT Motor_Feedback ]----( Output_Fault )Code Explanation:
- 1.Network 1: Input conditioning with Mitsubishi-specific TON timer for debouncing in Packaging environments
- 2.Network 2: Safety interlock chain ensuring Guarding around rotating and reciprocating parts compliance
- 3.Network 3: Main Packaging Automation control with manual override capability for maintenance
- 4.Network 4: Production counting using Mitsubishi CTU counter for batch tracking
- 5.Network 5: Output verification monitors actuator feedback - critical for intermediate to advanced applications
- 6.Online monitoring: Online connection in GX Works provides multiple monitoring modes observing PLC o
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
- ✓Ladder Logic: Keep rungs simple - split complex logic into multiple rungs for clarity
- ✓Ladder Logic: Use descriptive tag names that indicate function (e.g., Motor_Forward_CMD not M001)
- ✓Ladder Logic: Place most restrictive conditions first (leftmost) for faster evaluation
- ✓Packaging Automation: Use electronic gearing for mechanical simplicity
- ✓Packaging Automation: Implement automatic film/label splice detection
- ✓Packaging Automation: Add statistical monitoring of registration error
- ✓Debug with GX Works2/GX Works3: Use sampling trace to capture high-speed events occurring faster than
- ✓Safety: Guarding around rotating and reciprocating parts
- ✓Use GX Works2/GX Works3 simulation tools to test Packaging Automation logic before deployment
Common Pitfalls to Avoid
- ⚠Ladder Logic: Using the same OTE coil in multiple rungs (causes unpredictable behavior)
- ⚠Ladder Logic: Forgetting to include stop conditions in seal-in circuits
- ⚠Ladder Logic: Not using one-shots for counter inputs, causing multiple counts per event
- ⚠Mitsubishi common error: Error 2110: Illegal device specified - accessing device outside configured range
- ⚠Packaging Automation: Maintaining registration at high speeds
- ⚠Packaging Automation: Handling product variability in automated systems
- ⚠Neglecting to validate Product detection sensors for counting and positioning leads to control errors
- ⚠Insufficient comments make Ladder Logic programs unmaintainable over time