The Siemens 6ES5955-3LF11 is a high-power redundant power supply module designed for the SIMATIC S5-135U/150U/155U modular PLC systems. It serves as the primary power source for S5 control cabinets, delivering stable 5V DC power to support CPU, I/O, and communication modules. Below is a detailed technical overview based on historical Siemens documentation and industry records:
- Product Series: SIMATIC S5 (part of the S5-135U/150U/155U PLC systems)
- Module Type: Redundant power supply unit (PS 955)
- Product Status: Obsolete/Discontinued (replaced by modern SIMATIC S7-300/S7-1500 power supplies)
- Key Function: Provides 5V DC power to S5 PLC racks and supports redundant operation for fault tolerance.
The 6ES5955-3LF11 ensures reliable power distribution in S5 PLC systems, critical for industrial automation applications where downtime is costly. Its key roles include:
- Power Supply: Provides 5V DC power to all modules in the S5 rack, including CPUs, I/O modules, and communication processors.
- Redundancy:
- Operates in dual configuration to eliminate single points of failure.
- Monitors input voltage and output current, triggering alarms for faults.
- Compatibility:
- Works with S5-135U, S5-150U, and S5-155U central controllers.
- Supports expansion units (e.g., EU 185U) for large-scale systems.
典型应用场景:
- Manufacturing plants with continuous production lines.
- Power generation and water treatment facilities requiring high availability.
- Automotive assembly lines and chemical processing plants.
- Dual Power Supply Setup:
- Two 6ES5955-3LF11 modules are connected in parallel, with one acting as primary and the other as standby.
- The standby unit activates within milliseconds if the primary fails, ensuring uninterrupted power.
- Diagnostics:
- LED indicators show "Power OK," "Output OK," and "Redundancy Fault."
- Alarms can be routed to the PLC or external systems for remote monitoring.
As the S5 series is obsolete, Siemens recommends migrating to the SIMATIC S7-300/S7-1500 series, which offers:
- Higher efficiency and compact designs (e.g., S7-300 6ES7 307-1EA01-0AA0).
- Integration with TIA Portal engineering software for simplified configuration.
- Advanced diagnostics and predictive maintenance capabilities.
Recommended Replacement Models:
- S7-300: 6ES7 307-1EA01-0AA0 (5V DC, 10A) or 6ES7 307-1KA02-0AA0 (24V DC, 10A).
- S7-1500: 6ES7 507-0RA00-0AB0 (24V DC, 10A) or 6ES7 505-0RA00-0AB0 (24V DC, 5A).
- Legacy Manuals: Historical guides like "SIMATIC S5 Power Supply Manual" are available via Siemens’ legacy documentation archive.
- Third-Party Support: Specialized suppliers (e.g., 3S PLC) offer refurbished 6ES5955-3LF11 modules and migration services.
- Programming Tools: S5 systems require STEP 5 or STEP 7 V5.x (not compatible with TIA Portal).
- Spare Parts: Limited availability; plan for system modernization to avoid future downtime.
- Installation: Requires proper grounding and ventilation to ensure thermal stability.
For assistance with migration planning or troubleshooting, contact Siemens Industrial Support or a certified automation partner.
