Siemens 6EP1931-2FC21 SITOP UPS Module 24V DC 5A | Replacement, Equivalent & Selection Guide
The Siemens 6EP1931-2FC21 is a SITOP series uninterruptible power supply (UPS) module designed for 24V DC industrial control systems. It provides reliable bridging of power failures to protect PLCs, HMIs, and automation equipment from unexpected shutdowns. This page serves as a comprehensive selection guide, covering technical specifications, compatible replacements, and application scenarios to help engineers and procurement teams make informed decisions.
Technical Specifications
- Part Number: 6EP1931-2FC21
- Brand: Siemens
- Series: SITOP UPS500S
- Input Voltage: 24V DC (18–30V DC)
- Output Voltage: 24V DC
- Output Current: 5A
- Battery Type: Maintenance-free lead-acid battery module (external, e.g. 6EP1935-6ME21)
- Bridging Time: Depends on connected battery capacity and load
- Communication Interface: USB (for UPS configuration and monitoring)
- Signaling: Relay output for power failure / battery low alarm
- Mounting: DIN rail (35mm)
- Protection Class: IP20
- Operating Temperature: 0°C to +60°C
- Dimensions (W×H×D): Approx. 70 × 125 × 130 mm
- Weight: Approx. 1,020 g (without battery)
- Certifications: CE, UL, cULus
- MLFB / Order Number: 6EP1931-2FC21
Compatible Replacement & Equivalent Models
When the 6EP1931-2FC21 is unavailable or discontinued, the following models may serve as direct or functional replacements. Always verify electrical and mechanical compatibility before substitution.
- Siemens 6EP1931-2EC41 — SITOP UPS500S 24V/5A, earlier generation, functionally equivalent
- Siemens 6EP4134-0GB00-0AY0 — SITOP UPS1600 24V/10A, upgraded capacity alternative
- Phoenix Contact UPS-BAT/VRLA/24DC/5AH — Third-party 24V UPS battery module, compatible in similar architectures
- Weidmuller UPS24.241 — 24V DC UPS module, functional equivalent for DIN rail applications
- ABB CP-E 24/5.0 — 24V/5A power supply; pair with separate UPS buffer for equivalent function
Note: Cross-brand replacements require careful validation of input/output specs, communication protocols, and physical dimensions.
Why Choose the Original Model
- Seamless SIMATIC Integration: Native compatibility with Siemens S7-300, S7-400, S7-1200, and S7-1500 PLCs via STEP 7 / TIA Portal diagnostics
- USB Monitoring: Real-time UPS status monitoring and parameterization via PC software
- Proven Reliability: SITOP series is the industry benchmark for 24V DC industrial power in harsh environments
- Long Service Life: Designed for 24/7 continuous operation in industrial automation settings
- Compact DIN Rail Design: Minimal panel space with modular battery expansion
Typical Applications
- PLC cabinet power backup (Siemens S7 series, Allen-Bradley, Mitsubishi)
- HMI and operator panel uninterruptible power supply
- Industrial PC (IPC) and edge computing device protection
- Process control systems in chemical, pharmaceutical, and food & beverage industries
- Building automation and HVAC control panels
- Railway and transportation control systems
- Water treatment and utilities SCADA systems
System Compatibility
- Siemens SIMATIC S7-300 / S7-400 / S7-1200 / S7-1500 — Full native compatibility
- Siemens SITOP PSU100S / PSU200M — Designed to pair with SITOP power supplies
- Siemens WinCC / TIA Portal — Diagnostic integration via USB interface
- Third-party PLCs (Allen-Bradley, Mitsubishi, Omron): Compatible at 24V DC level; no native software integration
- Battery Module: Requires Siemens 6EP1935-6ME21 or equivalent VRLA battery pack
Selection Guide
Use the following criteria to select the correct UPS module for your application:
- Step 1 — Determine Load Current: Sum the 24V DC current draw of all protected devices. The 6EP1931-2FC21 supports up to 5A continuous output.
- Step 2 — Calculate Required Bridging Time: Estimate how long the system must run on battery (e.g., safe shutdown = 30 seconds; process completion = 5–10 minutes). Select battery capacity accordingly.
- Step 3 — Check Communication Requirements: If UPS status monitoring via PROFINET or PROFIBUS is required, consider upgrading to the SITOP UPS1600 series (6EP4134-0GB00-0AY0).
- Step 4 — Verify Panel Space: Confirm DIN rail space for both the UPS module and external battery module.
- Step 5 — Confirm Certifications: For UL-listed installations, verify the 6EP1931-2FC21 meets local electrical code requirements.
Quality Assurance & Sourcing
All products listed on Konmask.com are sourced through verified industrial distribution channels. The Siemens 6EP1931-2FC21 offered here is:
- ✅ Genuine Siemens product — not counterfeit or refurbished unless explicitly stated
- ✅ Inspected for physical integrity and label authenticity before shipment
- ✅ Shipped with original manufacturer packaging where available
- ✅ Backed by Konmask’s sourcing guarantee and after-sales support
For large-quantity orders or project procurement, contact our team for volume pricing and lead time confirmation.
How to Order
- Confirm the part number: 6EP1931-2FC21
- Specify required quantity
- Add to cart or contact us directly for bulk/project orders
- Our team will confirm stock availability and estimated delivery within 24 hours
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📞 Phone/WhatsApp: +0086 19859288691
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Replacement & Compatibility FAQ
Q: Is the 6EP1931-2FC21 still in production?
A: This model may be subject to lifecycle changes. Contact us to confirm current availability or to identify the recommended successor model.
Q: Can I use a third-party battery with the 6EP1931-2FC21?
A: The module is designed for Siemens SITOP battery modules. Third-party VRLA batteries with matching voltage and capacity may work but are not officially supported by Siemens.
Q: What is the difference between 6EP1931-2FC21 and 6EP1931-2EC41?
A: The 2FC21 is a newer revision with USB communication support; the 2EC41 is an earlier version without USB. Both provide 24V/5A UPS functionality.
Q: Does this UPS support PROFINET communication?
A: No. The 6EP1931-2FC21 uses USB for monitoring. For PROFINET-integrated UPS, refer to the SITOP UPS1600 series.
Q: Can Konmask source discontinued Siemens UPS modules?
A: Yes. We specialize in sourcing legacy and hard-to-find industrial automation components. Contact us with your part number and quantity.
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