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Robust Energy Source for SIMATIC S5-95U Controllers
The Siemens 6ES5955-3LF31 power supply unit delivers regulated DC power to S5-95U programmable controllers and their peripheral modules. This unit converts 120/230V AC mains voltage into stable 24V DC output for consistent system operation. It integrates seamlessly with the S5-95U base unit and supports up to 32 expansion modules through the backplane bus.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Siemens |
| Model | 6ES5955-3LF31 |
| Series | SIMATIC S5 |
| Product Type | Power Supply Unit |
| Input Voltage | 120/230V AC (selectable), 47-63 Hz |
| Output Voltage | 24V DC |
| Output Current | 2A |
| Output Power | 48W |
| Efficiency | Approx. 85% |
| Voltage Tolerance | ±3% |
| Residual Ripple | < 50 mVpp |
| Hold-up Time | ≥ 20 ms (at nominal load) |
| Protection Features | Overvoltage, short-circuit, and overload protection |
| LED Indicators | 1 x green “24V OK” |
| Operating Temperature | 0°C to 60°C |
| Weight | 0.9 kg |
| Dimensions (W x H x D) | 80 x 120 x 110 mm |
| Protection Rating | IP20 |
Comprehensive Protection Systems
The Siemens 6ES5955-3LF31 includes multiple safeguards for reliable power delivery in industrial environments. The overvoltage protection triggers automatically when output exceeds safe thresholds. Similarly, the short-circuit protection activates during wiring faults to prevent module damage. The overload protection ensures stable current output even during temporary demand spikes.
Power Reserve and Reliability
This unit provides 2A output current to supply both the CPU and a substantial number of I/O modules. The hold-up time of at least 20 milliseconds bridges brief power interruptions without system reset. The green “24V OK” LED offers immediate visual confirmation of normal operating status.
Mounting and System Integration
The power supply mounts directly onto the S5-95U base unit, eliminating external wiring and space requirements. This design reduces installation time and simplifies cabinet layouts. Furthermore, the 0.9 kg weight and compact dimensions facilitate mounting in standard enclosures.
Thermal Performance
The module operates reliably across a temperature range of 0°C to 60°C, covering most industrial applications. The efficient thermal design allows continuous operation without active cooling in standard conditions. The IP20 protection rating also ensures safe operation in controlled indoor environments.