HMI Development
HMI Development for Clearer, More Effective Machine Control
Human Machine Interfaces (HMIs) provide the connection between operators and industrial automation systems. A well-developed HMI should give operators the information and controls they need to understand machine conditions, respond to faults and operate equipment efficiently.
Poorly structured interfaces can make even a well-designed control system difficult to operate. Confusing navigation, inconsistent screens, unclear alarms and excessive information can increase operator error and make fault diagnosis unnecessarily difficult.
At Stratos, we develop industrial HMI applications around the equipment, process and people using them. From new machine interfaces to the redevelopment of existing HMI applications, our engineers create clear, structured operator environments integrated with your PLC and wider automation system.
What Is HMI Development?
HMI development is the process of designing and programming the graphical interface operators use to interact with industrial machinery and control systems.
An HMI can provide operators with access to:
Machine status.
Process information.
Equipment controls.
Operating modes.
Setpoints.
Alarms and faults.
Production information.
Diagnostic data.
Historical trends.
Effective HMI development combines automation engineering with clear information presentation so operators can understand the condition of the equipment quickly.
HMI Screen Design
Good HMI development starts with understanding what information operators actually need.
Rather than filling screens with every available PLC value, interfaces should prioritise information according to its operational importance.
HMI screen design may consider:
Clear information hierarchy.
Consistent layouts.
Equipment status.
Process conditions.
Navigation.
Alarm visibility.
Operator controls.
Diagnostic information.
Consistent design across screens makes the system easier to learn and helps operators locate important information more quickly.
PLC and HMI Integration
The HMI relies on information from the PLC controlling the machine or process.
Effective integration ensures commands, status information and process values are exchanged reliably between the two systems.
PLC and HMI integration may include:
Machine commands.
Operating modes.
Equipment status.
Process values.
Setpoints.
Alarm conditions.
Fault diagnostics.
Production information.
Stratos works across multiple PLC platforms, allowing HMI applications to be developed around both new and existing industrial control systems.
HMI Alarm and Fault Displays
When equipment fails, the HMI is often the first place an operator looks for information.
Clear alarm and fault displays can significantly improve the speed of diagnosis.
Effective HMI alarm development considers:
Clear fault descriptions.
Alarm priorities.
Equipment identification.
Alarm acknowledgement.
Active alarm visibility.
Historical alarms.
Diagnostic information.
Operator response requirements.
The objective is to provide meaningful information rather than simply displaying an error code.
HMI Navigation and Operator Usability
Operators should be able to move through an HMI logically without having to remember where important information is located.
Navigation can be structured around:
Production areas.
Individual machines.
Equipment groups.
Process stages.
Alarm screens.
Maintenance screens.
Settings.
Diagnostics.
A predictable navigation structure reduces unnecessary operator interaction and makes the interface easier to use during both normal production and fault conditions.
HMI Development for Machine Control
HMIs are commonly used as the primary operator interface for automated machinery.
Machine HMI applications may provide control of:
Machine start and stop.
Automatic and manual operation.
Production recipes.
Process setpoints.
Motor controls.
Equipment sequences.
Maintenance functions.
Production information.
The HMI is developed alongside the PLC control strategy so the interface accurately reflects how the machine operates.
HMI Modernisation and Upgrades
Older HMI hardware and software can become difficult to maintain as manufacturers discontinue products and engineering platforms.
HMI modernisation may involve:
Replacing obsolete operator panels.
Migrating existing HMI applications.
Updating screen layouts.
Improving navigation.
Reconfiguring PLC communications.
Improving alarms.
Adding diagnostic information.
Updating documentation.
Where possible, useful existing functionality can be retained while improving the overall operator experience.
HMI Development for Existing Machinery
Introducing a new HMI does not necessarily require replacing the entire control system.
Existing machinery can often benefit from a modern operator interface even when the underlying PLC remains suitable for continued operation.
Our engineers assess:
Existing PLC hardware.
Communication capabilities.
Current HMI application.
Machine functionality.
Available PLC data.
Operator requirements.
Existing documentation.
Future upgrade plans.
This allows the HMI solution to be developed around the equipment already in place.
HMI Diagnostics and Maintenance Information
HMIs can provide maintenance teams with considerably more information than basic machine controls.
Dedicated diagnostic screens may display:
PLC communication status.
Sensor conditions.
Input and output states.
Motor faults.
Drive status.
Safety conditions.
Sequence states.
Equipment interlocks.
Providing structured diagnostic information can help maintenance teams identify the source of a problem more quickly and reduce unnecessary fault-finding time.
HMI Testing and Commissioning
Every HMI application should be thoroughly tested before entering production.
Testing may include:
PLC communication.
Screen navigation.
Operator controls.
Setpoint validation.
Alarm functionality.
User permissions.
Equipment status.
Diagnostic information.
Functional testing.
Site commissioning.
Testing the HMI alongside the PLC and connected equipment helps ensure the information displayed to operators accurately represents the condition of the machine.
HMI User Access and Permissions
Not every operator or engineer requires access to the same HMI functions. User access can be structured to ensure different levels of control are available to the appropriate personnel.
Depending on the application, permissions may be configured for:
Machine operators.
Maintenance teams.
Engineers.
Supervisors.
Administrators.
Production management.
Access levels can restrict functions such as changing critical setpoints, modifying machine parameters, accessing maintenance controls or altering system configuration.
A structured approach to HMI user permissions helps protect important machine settings while still giving operators and engineering teams access to the functions they need to perform their roles effectively.
Why Choose Stratos for HMI Development?
Effective HMI development requires more than graphical design. The interface must accurately represent the PLC logic, machinery and industrial process behind it.
Stratos combines PLC programming, SCADA engineering and industrial automation expertise to develop HMI applications around the complete control system.
Whether you're developing a new machine, replacing an obsolete operator panel or improving an existing interface, our engineers create practical HMI solutions designed to improve usability, fault visibility and long-term maintainability.
Give Operators Better Control and Visibility
A good HMI makes complex automation easier to understand. Stratos develops industrial HMI applications that provide clear machine control, meaningful fault information and intuitive access to the data operators need. Speak to our engineers about developing or modernising the HMI for your industrial automation system.
Frequently Asked Questions
What is an HMI?
A Human Machine Interface (HMI) is the graphical interface that allows operators to monitor and interact with industrial machinery, PLCs and automated processes.
Can you develop an HMI for an existing PLC system?
Yes. New HMI applications can often be developed around existing PLC systems, provided suitable communication and access to the required PLC data are available.
Can an obsolete HMI be replaced?
Yes. Obsolete HMI hardware can often be replaced with a modern operator panel, with the existing application migrated, recreated or improved depending on compatibility and project requirements.
What information can an HMI display?
HMIs can display machine status, process values, alarms, equipment conditions, production information, setpoints, diagnostics and other information available from the PLC or control system.
What is the difference between an HMI and SCADA?
An HMI typically provides local monitoring and control of an individual machine or process, while SCADA generally provides wider supervisory monitoring, data acquisition and control across multiple machines, PLCs or production areas.