Migrating HMI Screens on Roll Forming Machines — Best Practices, Pitfalls & Commissioning

Introduction — Why HMI Migration Happens

Human Machine Interfaces (HMIs) are critical components of modern roll forming machines. They provide operators with the ability to control the machine, monitor production, and diagnose faults.

Older roll forming lines often use outdated HMI systems such as:

early touchscreen panels
monochrome operator terminals
proprietary manufacturer interfaces
unsupported software platforms.

When these systems fail or become obsolete, replacing the HMI becomes necessary. In many cases, the PLC may remain functional while only the operator interface needs upgrading.

Migrating HMI screens involves transferring the functionality of the old interface into a new HMI platform while maintaining reliable machine operation.

A successful migration improves:

operator usability
machine diagnostics
alarm visibility
production monitoring.

However, poorly executed migrations can introduce control errors and operational confusion.

Common Reasons for HMI Migration

HMI upgrades are typically performed for several reasons.

These include:

obsolete hardware no longer supported by manufacturers
failed display or touchscreen
lack of spare parts
poor operator interface design
integration with newer PLC platforms.

Many manufacturers take the opportunity to improve the interface when performing an upgrade.

Understanding the Original HMI System

Before beginning migration, engineers must understand how the existing HMI operates.

Important elements to identify include:

screen layout and navigation
PLC tag connections
alarm messages
operator input fields
recipe management.

Documentation of the original HMI system is essential.

Engineers should capture screenshots and export configuration files if possible.

Capturing Existing Screens

Before removing the old HMI, record every screen.

Documentation should include:

main operation screen
manual control pages
alarm pages
parameter setup pages
maintenance screens.

Photographs or screen captures help recreate the interface accurately.

Without documentation, recreating functionality becomes difficult.

Identifying PLC Tags

Every HMI screen communicates with PLC variables called tags.

Examples of common tags include:

machine start command
machine stop command
line speed display
panel length entry
alarm reset command.

When migrating the HMI, each tag must be mapped correctly to the new system.

Incorrect tag mapping can cause serious control problems.

Tag Naming Differences Between Platforms

Different HMI platforms may use different tag structures.

Examples include:

direct PLC addressing
symbolic tag names
network-based tag references.

During migration, engineers must adapt tag references to match the new system.

Careful mapping prevents communication errors.

Alarm System Migration

HMIs typically display alarms generated by the PLC.

During migration, alarm functionality must be transferred carefully.

Important elements include:

alarm messages
alarm priorities
reset behavior
alarm history logs.

Operators rely on alarm screens to diagnose machine problems.

Incomplete alarm migration can make troubleshooting difficult.

Operator Interface Design Improvements

Migrating to a modern HMI offers an opportunity to improve the interface.

Common improvements include:

clearer machine status displays
simplified navigation menus
larger control buttons
better alarm visibility.

A well-designed interface improves operator efficiency.

Screen Layout Best Practices

Effective HMI screens should follow several design principles.

Recommended practices include:

clear grouping of controls
consistent color coding
minimal screen clutter
large readable fonts.

Operators must be able to understand machine status quickly.

Overly complex screens can cause confusion during production.

Color Usage in HMI Design

Color coding helps operators recognize machine conditions.

Typical color conventions include:

green for running status
red for faults
yellow for warnings
blue for information.

Consistent color use improves usability.

Navigation Structure

Modern HMI interfaces typically use menu-based navigation.

Common screen groups include:

main production screen
manual control screen
alarm screen
maintenance screen
settings screen.

Clear navigation reduces operator training requirements.

Recipe System Migration

Many roll forming machines use recipe systems to store production settings.

Recipes may include:

panel length
line speed
punch positions
stacker parameters.

When migrating the HMI, recipe functionality must be preserved.

Operators must be able to load and modify recipes easily.

Data Logging and Production Tracking

New HMI systems often support data logging.

Typical data that may be recorded includes:

production counts
machine downtime
alarm history
operating hours.

These features improve production analysis.

Graphics and Symbol Conversion

Older HMIs may use outdated graphics formats.

When migrating screens, engineers may need to recreate graphics manually.

Common graphic elements include:

machine diagrams
button icons
status indicators.

Modern HMIs often support more advanced visual features.

Communication Setup

The new HMI must communicate with the PLC using compatible protocols.

Common industrial communication methods include:

Ethernet-based protocols
serial communication links
fieldbus systems.

Incorrect communication configuration will prevent HMI operation.

Security and Access Levels

Modern HMIs often include user authentication features.

Access levels may include:

operator access
maintenance access
engineer access.

This prevents unauthorized modification of machine settings.

Testing the New HMI System

Once migration is complete, the system must be tested thoroughly.

Testing steps include:

1 verifying PLC communication
2 checking every control button
3 verifying displayed values
4 testing alarm messages
5 confirming recipe functions.

Testing ensures the new interface works correctly.

Commissioning Best Practices

During commissioning, operators should test the system under real production conditions.

Typical commissioning tests include:

starting and stopping the machine
changing recipes
triggering alarm conditions.

These tests ensure the interface performs correctly during operation.

Common Migration Problems

Several issues may occur during HMI migration.

Typical problems include:

Incorrect tag mapping

If PLC addresses are wrong, controls may not work.

Missing alarms

If alarm messages are not transferred correctly, operators may lose important diagnostics.

Screen navigation errors

Incorrect screen links may prevent access to certain pages.

Careful testing helps detect these issues.

Documentation of the New HMI System

After migration, engineers should document the new system.

Documentation should include:

screen layouts
tag mapping lists
communication settings
software backups.

Proper documentation simplifies future maintenance.

Benefits of Modern HMI Systems

Upgrading the HMI provides several advantages.

These include:

better operator usability
improved diagnostics
easier machine monitoring
enhanced production control.

Modern interfaces significantly improve the usability of roll forming machines.

FAQ — HMI Migration

Why do roll forming machines require HMI upgrades?

Older HMI hardware may become obsolete or unsupported by manufacturers.

What is the most important step before migrating HMI screens?

Documenting the original screens and tag mappings.

Can the PLC remain unchanged during an HMI upgrade?

Yes. Many upgrades replace only the HMI while keeping the existing PLC.

What causes buttons to stop working after migration?

Incorrect tag mapping between the HMI and PLC.

Why is alarm migration important?

Operators rely on alarms to diagnose machine problems quickly.

Should the new HMI interface be redesigned?

Yes. Upgrading the interface provides an opportunity to improve usability and operator efficiency.