24V DC Uninterruptible Power Supply (Industrial-Grade Reliability)

The Siemens 6EP1931-2EC21 represents a critical infrastructure component for industrial automation environments demanding zero-tolerance power interruption. This DC UPS module safeguards programmable logic controllers, distributed I/O systems, and process instrumentation against voltage sags, brownouts, and complete mains failures. By maintaining continuous 24V DC output during grid disturbances, it prevents production halts, protects in-process materials, and ensures controlled equipment shutdown sequences.

Designed for integration with SITOP modular power supply ecosystems, this unit addresses the fundamental challenge facing modern manufacturing: power quality variability. Whether your facility experiences frequent utility fluctuations or requires compliance with safety shutdown protocols, the 6EP1931-2EC21 delivers transparent backup power that activates in under 10 milliseconds—faster than most control systems can detect the interruption.

Ideal for process engineers, automation integrators, and facility managers overseeing mission-critical operations in pharmaceuticals, food processing, semiconductor fabrication, and water treatment. This module transforms unpredictable power events into managed transitions, giving operators time to execute safe shutdown procedures or ride through brief outages without process disruption.

Core Capabilities & Business Value

✓ Seamless Transition Technology
Sub-10ms switchover ensures PLCs and sensors never detect power loss, eliminating nuisance faults and maintaining scan cycle integrity. Your automation programs continue executing without interruption or data corruption.

→ Intelligent Battery Management
Integrated charging circuit with temperature compensation extends battery service life by 30-40% compared to basic float charging. Automatic health diagnostics predict replacement needs before failures occur, reducing emergency maintenance calls.

✓ Scalable Backup Duration
Configurable runtime from 5 to 30+ minutes based on battery capacity selection. Right-size your investment: brief ride-through for momentary dips or extended backup for orderly process shutdown. Battery sizing calculator available upon request.

→ Parallel Operation Ready
Designed for seamless integration with SITOP PSU power supplies in redundant configurations. Combine with 6EP1334 or 6EP3334 series units for N+1 reliability architectures without custom engineering.

✓ Diagnostic Transparency
Multi-color LED indicators and relay alarm outputs provide instant visibility into power status, battery condition, and fault states. Integrate alarm signals into SCADA systems for centralized monitoring and predictive maintenance workflows.

→ Harsh Environment Durability
Operates reliably in 0°C to +60°C ambient temperatures with conformal coating protection against dust, humidity, and chemical vapors. DIN rail mounting simplifies installation in crowded control cabinets.

Industry Applications & Problem Resolution

Pharmaceutical Manufacturing
Maintains power to clean room environmental controls and batch process PLCs during utility switching events. Prevents costly batch losses and ensures FDA 21 CFR Part 11 data integrity by keeping data loggers operational during brief outages. Typical deployment: sterile filling lines, lyophilization chambers, and HVAC control systems.

Water & Wastewater Treatment
Protects SCADA RTUs and chemical dosing controllers from power interruptions that could cause environmental permit violations. Ensures lift station pumps receive controlled shutdown commands rather than abrupt power loss, preventing water hammer and mechanical damage. Critical for unmanned remote sites with unreliable grid connections.

Semiconductor Fabrication
Safeguards process tool controllers and gas cabinet safety systems where unexpected power loss could create hazardous conditions or destroy wafers in-process. The <10ms switching time meets stringent requirements for CVD, etch, and lithography equipment that cannot tolerate even momentary voltage dips.

Food & Beverage Processing
Keeps packaging line PLCs and vision inspection systems operational during brief power sags, preventing product giveaway errors and reducing line restart times. Maintains power to CIP (clean-in-place) system controllers to complete sanitization cycles even during utility disturbances.

Building Automation
Ensures fire alarm panels, access control systems, and emergency lighting controllers maintain operation during power transfer to backup generators. The 15-30 minute backup window bridges the gap until diesel generators reach full output voltage.

Technical Specifications & Selection Criteria

Selection Guidelines: Calculate total connected load including all PLCs, I/O modules, sensors, and communication devices. Add 20% safety margin for future expansion. For loads exceeding 12A continuous, consider the 6EP1931-2FC21 (40A model). Battery capacity should provide minimum 10 minutes runtime at full load; 15-20 minutes recommended for orderly shutdown. Use Siemens SITOP Battery Module 6EP1935-6MF01 (12Ah) for standard applications or 6EP1935-6MG01 (24Ah) for extended backup requirements.

Advanced Integration Features

Remote Monitoring Capability
Relay alarm contacts (Form C, 1A @ 30V DC) signal power failure, low battery, and battery fault conditions. Wire these outputs to PLC digital inputs or building management systems for automated notification and logging. Configure alarm thresholds via internal DIP switches to match your operational requirements.

Hot-Swap Battery Maintenance
Unique design allows battery replacement without interrupting connected loads when primary power is available. Schedule preventive battery changes during normal production hours rather than costly shutdown windows. Reduces mean time to repair (MTTR) from hours to minutes.

Modular System Expansion
Combine multiple UPS modules in parallel for higher current capacity or redundant backup configurations. Pair with SITOP PSU8200 or PSU8600 power supplies for complete power architecture solutions. All components share common 24V DC bus for simplified wiring and troubleshooting.

Energy Efficiency Optimization
Standby power consumption under 5W minimizes operating costs over 10+ year service life. High-efficiency switching topology reduces cabinet cooling requirements compared to linear UPS designs. Calculate total cost of ownership including energy savings and extended battery life.

Delivery Timeline & Service Commitment

Standard Lead Time: In-stock items ship within 2-3 business days via express courier (DHL, FedEx, UPS). Typical delivery to major industrial centers: 5-7 days Asia-Pacific, 7-10 days Europe/Americas. Expedited same-day shipping available for critical downtime situations (additional fees apply).

Warranty Coverage: Comprehensive 12-month manufacturer warranty covers defects in materials and workmanship under normal operating conditions. Extended warranty programs available for mission-critical applications. Warranty includes technical support for application questions and troubleshooting assistance.

Technical Support: Our automation specialists provide pre-sales engineering support including battery sizing calculations, system architecture review, and compatibility verification. Post-installation support includes configuration guidance, alarm integration assistance, and performance optimization recommendations. Email and phone support available during business hours (GMT+8).

Documentation Package: Each unit ships with installation manual, quick-start guide, wiring diagrams, and dimensional drawings. CAD files (DWG, STEP) and EPLAN macros available for download. Compliance certificates (CE, UL) provided upon request for project documentation requirements.

Frequently Asked Questions

What battery capacity do I need for 15 minutes of backup time at full load?
For 15A continuous load, we recommend a minimum 24Ah 12V battery (such as Siemens 6EP1935-6MG01). This provides approximately 18-20 minutes runtime accounting for battery aging and temperature derating. For lighter loads (8-10A typical), a 12Ah battery delivers 15-18 minutes. Use the formula: Runtime (hours) = Battery Ah × 0.8 ÷ Load Amps for conservative estimates.

Can this UPS module work with solar or wind power systems?
Yes, the 6EP1931-2EC21 accepts any stable 24V DC input source within the 18-31V range. It's commonly deployed in off-grid renewable energy installations to buffer intermittent power and provide backup during low-generation periods. Ensure your primary DC source can supply the load current plus 2-3A for battery charging.

How do I connect the alarm outputs to my PLC?
The module provides relay contacts (terminals 13-14-15) that close during fault conditions. Wire terminal 14 (common) to PLC digital input common, and terminal 13 or 15 to the input channel. Configure the PLC input for normally-open contact logic. Consult the installation manual page 12 for detailed wiring diagrams and alarm logic tables.

What's the expected battery replacement interval?
VRLA batteries in UPS applications typically require replacement every 3-5 years depending on ambient temperature, discharge cycles, and float voltage accuracy. The 6EP1931-2EC21's temperature-compensated charging extends this to 4-6 years in controlled environments (20-25°C). The module's battery test function (activated via front button) helps predict end-of-life 6-12 months in advance.

Is this suitable for outdoor installations or unheated buildings?
The module operates down to 0°C, but battery performance degrades significantly below 10°C. For outdoor or cold-environment applications, install the UPS and battery in a heated enclosure or specify cold-weather battery variants. Consult our technical team for Arctic-rated solutions if your application requires operation below -10°C.

Can I use automotive or deep-cycle batteries instead of VRLA types?
We strongly recommend sealed VRLA (valve-regulated lead-acid) batteries designed for standby/UPS applications. Automotive batteries are optimized for high-current cranking, not float charging, and will fail prematurely. Deep-cycle batteries may work but lack the low self-discharge characteristics needed for UPS duty. Using non-approved battery types may void warranty coverage.

Take the Next Step

Protect your critical automation infrastructure from costly power interruptions. Our technical team is ready to assist with battery sizing calculations, system architecture review, and compatibility verification for your specific application. Contact us today for a detailed quotation, technical data sheets, or to discuss volume pricing for multi-unit projects.

Request a Quote: Email your load requirements, desired backup time, and application details to our sales team.
Technical Consultation: Schedule a call with our automation specialists to review your power protection strategy.
Volume Discounts: Multi-unit pricing available for system integrators and OEM applications.

© 2026 NINERMAS COMPANY LIMITED. All rights reserved.
Original Source: https://ninermas.com
Contact: sale@ninermas.com | +0086 187 5021 5667