Learning to implement Communications for Motor Control using Unitronics's VisiLogic / UniLogic is an essential skill for PLC programmers working in Industrial Manufacturing. 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 Motor Control 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 beginner to intermediate complexity projects like Motor Control.
The Communications approach is particularly well-suited for Motor Control because multi-plc systems, scada integration, remote i/o, or industry 4.0 applications. This combination allows you to leverage system integration while managing the typical challenges of Motor Control, including soft start implementation and overload protection.
Throughout this guide, you'll discover step-by-step implementation strategies, working code examples tested on VisiLogic / UniLogic, and industry best practices specific to Industrial Manufacturing. Whether you're programming your first Motor Control system or transitioning from another PLC platform, this guide provides the practical knowledge you need to succeed with Unitronics Communications programming.
Unitronics VisiLogic / UniLogic for Motor Control
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 Motor Control:
- 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 Motor Control 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 Motor Control systems, including Current sensors, Vibration sensors, Temperature sensors.
Control Equipment for Motor Control:
- Motor control centers (MCCs)
- AC induction motors (NEMA/IEC frame)
- Synchronous motors for high efficiency
- DC motors for precise speed control
Unitronics's controller families for Motor Control include:
- Jazz 2: Suitable for beginner to intermediate Motor Control applications
- Samba 7": Suitable for beginner to intermediate Motor Control applications
- Vision V350: Suitable for beginner to intermediate Motor Control applications
- Vision V570: Suitable for beginner to intermediate Motor Control 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 Motor Control projects requiring beginner skill levels and 1-3 weeks development time, the total investment includes hardware, software licensing, training, and ongoing support.
Understanding Communications for Motor Control
Industrial communications connect PLCs to I/O, other controllers, HMIs, and enterprise systems. Protocol selection depends on requirements for speed, determinism, and compatibility.
Execution Model:
For Motor Control applications, Communications offers significant advantages when multi-plc systems, scada integration, remote i/o, or industry 4.0 applications.
Core Advantages for Motor Control:
- System integration: Critical for Motor Control when handling beginner to intermediate control logic
- Remote monitoring: Critical for Motor Control when handling beginner to intermediate control logic
- Data sharing: Critical for Motor Control when handling beginner to intermediate control logic
- Scalability: Critical for Motor Control when handling beginner to intermediate control logic
- Industry 4.0 ready: Critical for Motor Control when handling beginner to intermediate control logic
Why Communications Fits Motor Control:
Motor Control systems in Industrial Manufacturing typically involve:
- Sensors: Current transformers for motor current monitoring, RTD or thermocouple for motor winding temperature, Vibration sensors for bearing monitoring
- Actuators: Contactors for direct-on-line starting, Soft starters for reduced voltage starting, Variable frequency drives for speed control
- Complexity: Beginner to Intermediate with challenges including Managing starting current within supply limits
Programming Fundamentals in Communications:
Communications in VisiLogic / UniLogic follows these key principles:
1. Structure: Communications organizes code with remote monitoring
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 Communications:
- Use managed switches for industrial Ethernet
- Implement proper network segmentation (OT vs IT)
- Monitor communication health with heartbeat signals
- Plan for communication failure modes
- Document network architecture including IP addresses
Common Mistakes to Avoid:
- Mixing control and business traffic on same network
- No redundancy for critical communications
- Insufficient timeout handling causing program hangs
- Incorrect byte ordering (endianness) between systems
Typical Applications:
1. Factory networks: Directly applicable to Motor Control
2. Remote monitoring: Related control patterns
3. Data collection: Related control patterns
4. Distributed control: Related control patterns
Understanding these fundamentals prepares you to implement effective Communications solutions for Motor Control using Unitronics VisiLogic / UniLogic.
Implementing Motor Control with Communications
Motor control systems use PLCs to start, stop, and regulate electric motors in industrial applications. These systems provide protection, speed control, and coordination for motors ranging from fractional horsepower to thousands of horsepower.
This walkthrough demonstrates practical implementation using Unitronics VisiLogic / UniLogic and Communications programming.
System Requirements:
A typical Motor Control implementation includes:
Input Devices (Sensors):
1. Current transformers for motor current monitoring: Critical for monitoring system state
2. RTD or thermocouple for motor winding temperature: Critical for monitoring system state
3. Vibration sensors for bearing monitoring: Critical for monitoring system state
4. Speed encoders or tachometers: Critical for monitoring system state
5. Torque sensors for load monitoring: Critical for monitoring system state
Output Devices (Actuators):
1. Contactors for direct-on-line starting: Primary control output
2. Soft starters for reduced voltage starting: Supporting control function
3. Variable frequency drives for speed control: Supporting control function
4. Brakes (mechanical or dynamic): Supporting control function
5. Starters (star-delta, autotransformer): Supporting control function
Control Equipment:
- Motor control centers (MCCs)
- AC induction motors (NEMA/IEC frame)
- Synchronous motors for high efficiency
- DC motors for precise speed control
Control Strategies for Motor Control:
1. Primary Control: Industrial motor control using PLCs for start/stop, speed control, and protection of electric motors.
2. Safety Interlocks: Preventing Soft start implementation
3. Error Recovery: Handling Overload protection
Implementation Steps:
Step 1: Calculate motor starting current and verify supply capacity
In VisiLogic / UniLogic, calculate motor starting current and verify supply capacity.
Step 2: Select starting method based on motor size and load requirements
In VisiLogic / UniLogic, select starting method based on motor size and load requirements.
Step 3: Configure motor protection with correct thermal curve
In VisiLogic / UniLogic, configure motor protection with correct thermal curve.
Step 4: Implement control logic for start/stop with proper interlocks
In VisiLogic / UniLogic, implement control logic for start/stop with proper interlocks.
Step 5: Add speed control loop if VFD is used
In VisiLogic / UniLogic, add speed control loop if vfd is used.
Step 6: Configure acceleration and deceleration ramps
In VisiLogic / UniLogic, configure acceleration and deceleration ramps.
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. Managing starting current within supply limits
- Solution: Communications addresses this through System integration.
2. Coordinating acceleration with driven load requirements
- Solution: Communications addresses this through Remote monitoring.
3. Protecting motors from frequent starting (thermal cycling)
- Solution: Communications addresses this through Data sharing.
4. Handling regenerative energy during deceleration
- Solution: Communications addresses this through Scalability.
Safety Considerations:
- Proper machine guarding for rotating equipment
- Emergency stop functionality with safe torque off
- Lockout/tagout provisions for maintenance
- Arc flash protection and PPE requirements
- Proper grounding and bonding
Performance Metrics:
- Scan Time: Optimize for 5 inputs and 5 outputs
- Memory Usage: Efficient data structures for Jazz 2 capabilities
- Response Time: Meeting Industrial Manufacturing requirements for Motor Control
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 1-3 weeks development timeline while maintaining code quality.
Unitronics Communications Example for Motor Control
Complete working example demonstrating Communications implementation for Motor Control using Unitronics VisiLogic / UniLogic. Follows Unitronics naming conventions. Tested on Jazz 2 hardware.
// Unitronics VisiLogic / UniLogic - Motor Control Control
// Communications Implementation for Industrial Manufacturing
// Unitronics projects use IDE-managed tag names rather than ra
// ============================================
// Variable Declarations
// ============================================
VAR
bEnable : BOOL := FALSE;
bEmergencyStop : BOOL := FALSE;
rCurrentsensors : REAL;
rMotorstarters : REAL;
END_VAR
// ============================================
// Input Conditioning - Current transformers for motor current monitoring
// ============================================
// Standard input processing
IF rCurrentsensors > 0.0 THEN
bEnable := TRUE;
END_IF;
// ============================================
// Safety Interlock - Proper machine guarding for rotating equipment
// ============================================
IF bEmergencyStop THEN
rMotorstarters := 0.0;
bEnable := FALSE;
END_IF;
// ============================================
// Main Motor Control Control Logic
// ============================================
IF bEnable AND NOT bEmergencyStop THEN
// Motor control systems use PLCs to start, stop, and regulate
rMotorstarters := rCurrentsensors * 1.0;
// Process monitoring
// Add specific control logic here
ELSE
rMotorstarters := 0.0;
END_IF;Code Explanation:
- 1.Communications structure optimized for Motor Control in Industrial Manufacturing applications
- 2.Input conditioning handles Current transformers for motor current monitoring signals
- 3.Safety interlock ensures Proper machine guarding for rotating equipment always takes priority
- 4.Main control implements Motor control systems use PLCs to start,
- 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
- ✓Communications: Use managed switches for industrial Ethernet
- ✓Communications: Implement proper network segmentation (OT vs IT)
- ✓Communications: Monitor communication health with heartbeat signals
- ✓Motor Control: Verify motor running with current or speed feedback, not just contactor status
- ✓Motor Control: Implement minimum off time between starts for motor cooling
- ✓Motor Control: Add phase loss and phase reversal protection
- ✓Debug with VisiLogic / UniLogic: Use the built-in simulator to reproduce issues before hardware visit
- ✓Safety: Proper machine guarding for rotating equipment
- ✓Use VisiLogic / UniLogic simulation tools to test Motor Control logic before deployment
Common Pitfalls to Avoid
- ⚠Communications: Mixing control and business traffic on same network
- ⚠Communications: No redundancy for critical communications
- ⚠Communications: Insufficient timeout handling causing program hangs
- ⚠Unitronics common error: VisiLogic-to-UniLogic migration issues — not all projects convert cleanly
- ⚠Motor Control: Managing starting current within supply limits
- ⚠Motor Control: Coordinating acceleration with driven load requirements
- ⚠Neglecting to validate Current transformers for motor current monitoring leads to control errors
- ⚠Insufficient comments make Communications programs unmaintainable over time
Related Certifications
Mastering Communications for Motor Control applications using Unitronics VisiLogic / UniLogic requires understanding both the platform's capabilities and the specific demands of Industrial Manufacturing. This guide has provided comprehensive coverage of implementation strategies, working code examples, best practices, and common pitfalls to help you succeed with beginner to intermediate Motor Control 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 Industrial Manufacturing applications where Motor Control reliability is critical.
By following the practices outlined in this guide—from proper program structure and Communications best practices to Unitronics-specific optimizations—you can deliver reliable Motor Control systems that meet Industrial Manufacturing 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 Industrial Manufacturing applications
3. Hands-on Practice: Build Motor Control projects using Jazz 2 hardware
4. Stay Current: Follow VisiLogic / UniLogic updates and new Communications features
Communications Foundation:
Industrial communications connect PLCs to I/O, other controllers, HMIs, and enterprise systems. Protocol selection depends on requirements for speed, ...
The 1-3 weeks typical timeline for Motor Control projects will decrease as you gain experience with these patterns and techniques. Remember: Verify motor running with current or speed feedback, not just contactor status
For further learning, explore related topics including Remote monitoring, Fan systems, and Unitronics platform-specific features for Motor Control optimization.