Learning to implement Function Blocks for Packaging Automation using Unitronics's VisiLogic / UniLogic is an essential skill for PLC programmers working in Packaging. This comprehensive guide walks you through the fundamentals, providing clear explanations and practical examples that you can apply immediately to real-world projects.
Unitronics has established itself as Moderate - US small-integrator market, OEM machines, building automation, making it a strategic choice for Packaging Automation applications. With 1% global market share and 6 popular PLC families including the Jazz 2 and Samba 7", Unitronics provides the robust platform needed for intermediate to advanced complexity projects like Packaging Automation.
The Function Blocks approach is particularly well-suited for Packaging Automation because process control, continuous operations, modular programming, and signal flow visualization. This combination allows you to leverage visual representation of signal flow while managing the typical challenges of Packaging Automation, including product changeover and high-speed synchronization.
Throughout this guide, you'll discover step-by-step implementation strategies, working code examples tested on VisiLogic / UniLogic, and industry best practices specific to Packaging. Whether you're programming your first Packaging Automation system or transitioning from another PLC platform, this guide provides the practical knowledge you need to succeed with Unitronics Function Blocks programming.
Unitronics VisiLogic / UniLogic for Packaging Automation
Unitronics takes a distinctive approach to PLC programming: every controller ships with an integrated colour touchscreen HMI, and the development tool handles PLC logic and HMI design in a single workspace. VisiLogic is the legacy tool for the Vision, Samba, and Jazz product families; UniLogic is the current-generation environment for the UniStream line. Both are free to download and include a complete built-in simulator covering PLC logic, HMI screens, alarms, recipes, and data tables — the sim...
Platform Strengths for Packaging Automation:
- Combined PLC + HMI in one unit reduces panel cost
- Free VisiLogic and UniLogic IDEs
- Built-in simulator with both PLC and HMI simulation
- Strong US small-integrator community
Unique ${brand.software} Features:
- Combined PLC + HMI in one unit across Jazz, Samba, Vision, and UniStream
- Free VisiLogic (legacy) and UniLogic (current) IDEs
- Built-in simulator covering PLC logic, HMI, alarms, data tables, and recipes
- Integrated data sampling and trend logging without separate SCADA
Key Capabilities:
The VisiLogic / UniLogic environment excels at Packaging Automation applications through its combined plc + hmi in one unit reduces panel cost. 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)
Unitronics's controller families for Packaging Automation include:
- Jazz 2: Suitable for intermediate to advanced Packaging Automation applications
- Samba 7": Suitable for intermediate to advanced Packaging Automation applications
- Vision V350: Suitable for intermediate to advanced Packaging Automation applications
- Vision V570: Suitable for intermediate to advanced Packaging Automation applications
Hardware Selection Guidance:
CPU selection across Unitronics ranges from the Jazz 2 micro series (tiny applications, basic motor control, simple process monitoring with 10-20 I/O) through Samba 7" (small machine control with touchscreen HMI), Vision V350/V570 (medium machinery with larger HMI), and UniStream 7" / 15.6" (flagship combined PLC+HMI for mid-to-high complexity applications with advanced features like UniCloud, cel...
Industry Recognition:
Moderate - US small-integrator market, OEM machines, building automation. Unitronics' combined PLC+HMI controllers are uncommon in high-volume automotive manufacturing but appear in automotive tier-2 and tier-3 supplier shops, single-machine workcells, and after-market test fixtures. The cost advantage and single-unit PLC+HMI approach makes Unitronics attractive for small...
Investment Considerations:
With $$ pricing, Unitronics 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 Function Blocks for Packaging Automation
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 Packaging Automation:
- Visual representation of signal flow: Critical for Packaging Automation when handling intermediate to advanced control logic
- Good for modular programming: Critical for Packaging Automation when handling intermediate to advanced control logic
- Reusable components: Critical for Packaging Automation when handling intermediate to advanced control logic
- Excellent for process control: Critical for Packaging Automation when handling intermediate to advanced control logic
- Good for continuous operations: Critical for Packaging Automation when handling intermediate to advanced control logic
Why Function Blocks 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 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 Packaging Automation
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 Packaging Automation using Unitronics VisiLogic / UniLogic.
Implementing Packaging Automation with Function Blocks
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 Unitronics VisiLogic / UniLogic and Function Blocks 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 VisiLogic / UniLogic, define packaging specifications for all product variants.
Step 2: Create motion profiles for each packaging format
In VisiLogic / UniLogic, create motion profiles for each packaging format.
Step 3: Implement registration control with encoder feedback
In VisiLogic / UniLogic, implement registration control with encoder feedback.
Step 4: Program pattern generation for case and pallet loading
In VisiLogic / UniLogic, program pattern generation for case and pallet loading.
Step 5: Add reject handling with confirmation logic
In VisiLogic / UniLogic, add reject handling with confirmation logic.
Step 6: Implement barcode/vision integration for verification
In VisiLogic / UniLogic, implement barcode/vision integration for verification.
Unitronics Function Design:
Function block design in Unitronics uses user-defined FBs in UniLogic (more limited in VisiLogic). Extensive vendor-provided helper FBs cover common tasks (PID, motion, communication, HMI utilities). OEM machine builders typically maintain private FB libraries for their common machine patterns, though code reuse is less mature than in mainstream PLC ecosystems.
Common Challenges and Solutions:
1. Maintaining registration at high speeds
- Solution: Function Blocks addresses this through Visual representation of signal flow.
2. Handling product variability in automated systems
- Solution: Function Blocks addresses this through Good for modular programming.
3. Quick changeover between package formats
- Solution: Function Blocks addresses this through Reusable components.
4. Synchronizing multiple machines in a line
- Solution: Function Blocks addresses this through Excellent for process control.
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 Jazz 2 capabilities
- Response Time: Meeting Packaging requirements for Packaging Automation
Unitronics Diagnostic Tools:
UniLogic (current) and VisiLogic (legacy) integrated debuggers with breakpoints,Built-in simulator covering PLC logic, HMI screens, alarms, recipes, and data tables,Web visualisation for UniStream — remote HMI viewing without additional software,SD card logging with PC-side export tools for offline trend analysis,Modbus RTU/TCP transaction logging built into the IDE,Controller status monitor — CPU load, scan time, memory usage,HMI event logger capturing operator actions for audit purposes,CAN bus diagnostic tools for CANopen-equipped models,Remote support tool — Unitronics' own screen-sharing for technical support,User community forum with active troubleshooting discussions
Unitronics's VisiLogic / UniLogic provides tools for performance monitoring and optimization, essential for achieving the 3-6 weeks development timeline while maintaining code quality.
Unitronics Function Blocks Example for Packaging Automation
Complete working example demonstrating Function Blocks implementation for Packaging Automation using Unitronics VisiLogic / UniLogic. Follows Unitronics naming conventions. Tested on Jazz 2 hardware.
(* Unitronics VisiLogic / UniLogic - Packaging Automation Control *)
(* Reusable Function Blocks Implementation *)
(* Function block design in Unitronics uses user-defined FBs in *)
FUNCTION_BLOCK FB_PACKAGING_AUTOMATION_Controller
VAR_INPUT
bEnable : BOOL; (* Enable control *)
bReset : BOOL; (* Fault reset *)
rProcessValue : REAL; (* Product detection sensors for counting and positioning *)
rSetpoint : REAL := 100.0; (* Target value *)
bEmergencyStop : BOOL; (* Safety input *)
END_VAR
VAR_OUTPUT
rControlOutput : REAL; (* Servo drives for precise motion control *)
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; (* Alarm handling uses UniLogic's built-in Alarm Manager — configure alarm conditions in tables with severity, message text, and logging behaviour, and the engine handles detection, acknowledgement, history, and HMI display without custom code. VisiLogic uses a simpler alarm approach via HMI event handlers. *)
(* Internal State *)
eInternalState : E_ControlState;
tonWatchdog : TON;
END_VAR
(* Safety Monitor - Guarding around rotating and reciprocating parts *)
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, (* Packaging 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 - Safety-rated position monitoring for setup access *)
rControlOutput := 0.0;
bRunning := FALSE;
bFault := NOT bEnable; (* Only fault if not intentional stop *)
nFaultCode := fbSafety.FaultCode;
END_IF;
(* Diagnostics - Data logging uses UniLogic's Data Samplers — configured triggers (time-based or event-based) write structured records to Data Tables or SD card in CSV format. Exported files can be pushed via FTP or email. For cloud integration, UniCloud provides managed data ingestion. Simpler VisiLogic projects use HMI-triggered SD writes via custom ladder code. *)
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 block design in Unitronics uses - reusable across Packaging projects
- 2.FB_SafetyMonitor provides Guarding around rotating and reciprocating parts including high/low limits
- 3.FB_RampGenerator prevents startup issues common in Packaging Automation systems
- 4.FB_PIDController tuned for Packaging: Kp=1.0, Ki=0.1
- 5.Watchdog timer detects frozen control - critical for intermediate to advanced Packaging Automation reliability
- 6.Diagnostic function block enables Data logging uses UniLogic's Data Samplers — configured triggers (time-based or event-based) write structured records to Data Tables or SD card in CSV format. Exported files can be pushed via FTP or email. For cloud integration, UniCloud provides managed data ingestion. Simpler VisiLogic projects use HMI-triggered SD writes via custom ladder code. and Alarm handling uses UniLogic's built-in Alarm Manager — configure alarm conditions in tables with severity, message text, and logging behaviour, and the engine handles detection, acknowledgement, history, and HMI display without custom code. VisiLogic uses a simpler alarm approach via HMI event handlers.
Best Practices
- ✓Follow Unitronics naming conventions: Unitronics projects use IDE-managed tag names rather than raw memory addressing.
- ✓Unitronics function design: Function block design in Unitronics uses user-defined FBs in UniLogic (more limi
- ✓Data organization: Unitronics uses its own tag database concept rather than IEC-standard data block
- ✓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
- ✓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 VisiLogic / UniLogic: Use the built-in simulator to reproduce issues before hardware visit
- ✓Safety: Guarding around rotating and reciprocating parts
- ✓Use VisiLogic / UniLogic simulation tools to test Packaging Automation 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
- ⚠Unitronics common error: VisiLogic-to-UniLogic migration issues — not all projects convert cleanly
- ⚠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 Function Blocks programs unmaintainable over time
Related Certifications
Mastering Function Blocks for Packaging Automation applications using Unitronics VisiLogic / UniLogic requires understanding both the platform's capabilities and the specific demands of Packaging. This guide has provided comprehensive coverage of implementation strategies, working code examples, best practices, and common pitfalls to help you succeed with intermediate to advanced Packaging Automation projects.
Unitronics's 1% market share and moderate - us small-integrator market, oem machines, building automation demonstrate the platform's capability for demanding applications. The platform excels in Packaging applications where Packaging Automation reliability is critical.
By following the practices outlined in this guide—from proper program structure and Function Blocks best practices to Unitronics-specific optimizations—you can deliver reliable Packaging Automation systems that meet Packaging requirements.
Next Steps for Professional Development:
1. Certification: Pursue Unitronics Certified Integrator to validate your Unitronics expertise
2. Advanced Training: Consider UniLogic Developer Training for specialized Packaging applications
3. Hands-on Practice: Build Packaging Automation projects using Jazz 2 hardware
4. Stay Current: Follow VisiLogic / UniLogic updates and new Function Blocks features
Function Blocks Foundation:
Function Block Diagram (FBD) is a graphical programming language where functions and function blocks are represented as boxes connected by signal line...
The 3-6 weeks typical timeline for Packaging Automation projects will decrease as you gain experience with these patterns and techniques. Remember: Use electronic gearing for mechanical simplicity
For further learning, explore related topics including Temperature control, Pharmaceutical blister packing, and Unitronics platform-specific features for Packaging Automation optimization.