As hyperscale and enterprise data centers expand, power disruptions can cause service outages that affect thousands of users and can cost operators hundreds of thousands of dollars per hour.
While much attention is paid to generators themselves, the quality of the diesel fuel that powers them is crucial.
AXI International, a manufacturer of fuel management and polishing systems, develops automated solutions designed to ensure that stored diesel fuel remains sludge-free and generator-ready. To control these systems, the company integrates Unitronics UniStream PLC + HMI controllers, providing automated fuel maintenance, real-time monitoring, and alarm management to ensure backup power systems remain ready when needed.
The Growing Role of Fuel Management in Data Center Reliability
Contaminants settle in storage tanks and can clog filters, damage injectors, or prevent generators from starting during an emergency.
Fuel polishing systems mitigate these risks by continuously filtering, conditioning, and circulating stored diesel fuel, removing contaminants and maintaining generator readiness.
The Engineering Challenge
AXI International set out to develop a new generation of automated fuel polishing systems capable of supporting the operational demands of modern data centers.
Key requirements included:
- Industrial PLC control to manage pumps, valves, and filtration cycles
- Intuitive operator interface for data center technicians
- Automated scheduling for routine fuel maintenance cycles
- Alarm management and diagnostics for proactive maintenance
- Integration with remote monitoring systems
Because data centers operate continuously, the system also had to support predictive monitoring and remote diagnostics to minimize on-site intervention.
The Automation Solution
AXI International selected the Unitronics UniStream® PLC + HMI platform as the core of their FPS, STS, and MTC product lines. This integration replaced fragmented control components with a unified industrial architecture capable of managing complex filtration schedules and multi-tank transfers and remove water, sludge, and other contaminants from diesel storage tanks.
Using scheduled filtration routines configured through the HMI, the system circulates fuel through filters and water separators. Runtime conflicts are automatically detected, preventing pump operation during restricted intervals.
This level of automation allows operators to maintain fuel quality without manual intervention.
Direct Data Center Integration via Redfish
A key technical advantage for data center applications is UniStream’s native support for Redfish. As the industry-standard RESTful API for data center infrastructure management, Redfish enables the UniStream PLC to communicate directly with IT-side management systems. This allows operational technology—such as fuel polishing, cooling, or power systems—to move beyond isolated “islands of automation” and instead function as transparent, interoperable nodes within a DCIM (Data Center Infrastructure Management) environment.
Operator Interface and Control
Preconfigured HMI screens allow facility personnel to configure and monitor the system directly from the controller’s touchscreen interface.
Operators can:
- Schedule automatic fuel polishing routines
- Monitor tank levels and fuel condition indicators
- Switch between automatic and manual operation modes
- Transfer fuel between multiple tanks
- View system diagnostics and maintenance alerts
Additional system options can be configured directly through the HMI, including:
- Fuel heater control for cold environments
- Automatic water drain management
- Multi-point extraction for large or baffled tanks
- Filter monitoring using pressure transmitters
Remote Monitoring and Data Center Integration
For modern data centers, infrastructure monitoring extends beyond local control panels. AXI’s system leverages UniStream communication capabilities to integrate with broader monitoring architectures.
Features include:
Remote HMI Access: Using VNC with user access control, authorized personnel can remotely access the system interface for troubleshooting and diagnostics.
Industrial Communication Protocols: Built-in Modbus communication enables integration with sensors, instrumentation, and supervisory control systems.
DCIM Integration
Fuel system data can be incorporated into Data Center Infrastructure Management (DCIM) platforms, enabling centralized monitoring alongside power distribution, cooling systems, and other facility assets.
Alarm Management and Predictive Maintenance
Fuel system reliability is supported by UniStream’s integrated alarm management system.
Operators can configure alarm thresholds for:
- Vacuum levels
- Pump pressure
- Flow conditions
- Filter differential pressure
Alarm events are categorized by severity—critical, major, minor, or warning—and displayed through on-screen notifications and alarm banners.
The system can automatically:
- Send alarm notifications to designated personnel
- Generate daily operational reports
- Log alarm histories for maintenance analysis
These capabilities allow operators to address developing issues before they affect generator readiness.
Operational Impact
By combining automated fuel maintenance with integrated monitoring and alarm management, AXI’s fuel polishing systems help data centers maintain generator reliability while reducing manual maintenance requirements.
Key benefits include:
- Continuous diesel fuel conditioning
- Improved generator readiness
- Reduced risk of fuel-related generator failures
- Early detection of maintenance issues
- Integration with data center monitoring platforms
Conclusion
Backup power systems remain a critical component of data center resilience. Ensuring those systems function correctly during an emergency requires more than reliable generators—it requires maintaining fuel quality over long storage periods.
By integrating automated fuel polishing with Unitronics UniStream PLC + HMI controllers, AXI International has developed systems that help data centers maintain clean diesel fuel, monitor system performance, and detect potential issues before they threaten uptime.
As data center energy demand continues to grow, automated fuel maintenance systems are becoming an increasingly important layer of infrastructure protection—helping operators ensure backup power is ready when it is needed most.
