Learning to implement Counters for Material Handling using Unitronics's VisiLogic / UniLogic is an essential skill for PLC programmers working in Logistics & Warehousing. 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 Material Handling 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 Material Handling.
The Counters approach is particularly well-suited for Material Handling because counting parts, cycles, events, or maintaining production totals. This combination allows you to leverage essential for production tracking while managing the typical challenges of Material Handling, including route optimization and traffic management.
Throughout this guide, you'll discover step-by-step implementation strategies, working code examples tested on VisiLogic / UniLogic, and industry best practices specific to Logistics & Warehousing. Whether you're programming your first Material Handling system or transitioning from another PLC platform, this guide provides the practical knowledge you need to succeed with Unitronics Counters programming.
Unitronics VisiLogic / UniLogic for Material Handling
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 Material Handling:
- 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 Material Handling 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 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)
Unitronics's controller families for Material Handling include:
- Jazz 2: Suitable for intermediate to advanced Material Handling applications
- Samba 7": Suitable for intermediate to advanced Material Handling applications
- Vision V350: Suitable for intermediate to advanced Material Handling applications
- Vision V570: Suitable for intermediate to advanced Material Handling 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 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 Counters for Material Handling
PLC counters track the number of events or items. They increment or decrement on input transitions and compare against preset values.
Execution Model:
For Material Handling applications, Counters offers significant advantages when counting parts, cycles, events, or maintaining production totals.
Core Advantages for Material Handling:
- Essential for production tracking: Critical for Material Handling when handling intermediate to advanced control logic
- Simple to implement: Critical for Material Handling when handling intermediate to advanced control logic
- Reliable and accurate: Critical for Material Handling when handling intermediate to advanced control logic
- Easy to understand: Critical for Material Handling when handling intermediate to advanced control logic
- Widely used: Critical for Material Handling when handling intermediate to advanced control logic
Why Counters 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 Counters:
Counters in VisiLogic / UniLogic 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 Material Handling
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 Material Handling using Unitronics VisiLogic / UniLogic.
Implementing Material Handling with Counters
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 Unitronics VisiLogic / UniLogic and Counters 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 VisiLogic / UniLogic, map all storage locations with addressing scheme.
Step 2: Define product characteristics (size, weight, handling requirements)
In VisiLogic / UniLogic, define product characteristics (size, weight, handling requirements).
Step 3: Implement location tracking database interface
In VisiLogic / UniLogic, implement location tracking database interface.
Step 4: Program crane/shuttle motion control with positioning
In VisiLogic / UniLogic, program crane/shuttle motion control with positioning.
Step 5: Add load verification (presence, dimension, weight)
In VisiLogic / UniLogic, add load verification (presence, dimension, weight).
Step 6: Implement WMS interface for task assignment
In VisiLogic / UniLogic, implement wms interface for task assignment.
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 inventory accuracy in real-time
- Solution: Counters addresses this through Essential for production tracking.
2. Handling damaged or misplaced loads
- Solution: Counters addresses this through Simple to implement.
3. Coordinating multiple cranes in same aisle
- Solution: Counters addresses this through Reliable and accurate.
4. Optimizing storage assignment dynamically
- Solution: Counters addresses this through Easy to understand.
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 Jazz 2 capabilities
- Response Time: Meeting Logistics & Warehousing requirements for Material Handling
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 4-12 weeks development timeline while maintaining code quality.
Unitronics Counters Example for Material Handling
Complete working example demonstrating Counters implementation for Material Handling using Unitronics VisiLogic / UniLogic. Follows Unitronics naming conventions. Tested on Jazz 2 hardware.
// Unitronics VisiLogic / UniLogic - Material Handling Control
// Counters Implementation for Logistics & Warehousing
// Unitronics projects use IDE-managed tag names rather than ra
// ============================================
// 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.Counters 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 Jazz 2 (typically 5-20ms)
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
- ✓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
- ✓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 VisiLogic / UniLogic: Use the built-in simulator to reproduce issues before hardware visit
- ✓Safety: Aisle entry protection with light curtains and interlocks
- ✓Use VisiLogic / UniLogic simulation tools to test Material Handling 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
- ⚠Unitronics common error: VisiLogic-to-UniLogic migration issues — not all projects convert cleanly
- ⚠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 Counters programs unmaintainable over time
Related Certifications
Mastering Counters for Material Handling applications using Unitronics VisiLogic / UniLogic requires understanding both the platform's capabilities and the specific demands of Logistics & Warehousing. 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 Material Handling 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 Logistics & Warehousing applications where Material Handling reliability is critical.
By following the practices outlined in this guide—from proper program structure and Counters best practices to Unitronics-specific optimizations—you can deliver reliable Material Handling systems that meet Logistics & Warehousing 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 Logistics & Warehousing applications
3. Hands-on Practice: Build Material Handling projects using Jazz 2 hardware
4. Stay Current: Follow VisiLogic / UniLogic updates and new Counters features
Counters Foundation:
PLC counters track the number of events or items. They increment or decrement on input transitions and compare against preset values....
The 4-12 weeks typical timeline for Material Handling projects will decrease as you gain experience with these patterns and techniques. Remember: Verify load presence before and after each move
For further learning, explore related topics including Conveyor tracking, AGV systems, and Unitronics platform-specific features for Material Handling optimization.