SIEMENS SIMATIC 6ES5955-3NF41

SIEMENS SIMATIC 6ES5955-3NF41 – Memory Module for SIMATIC S5 PLC Systems

Non-Volatile Backup Memory for S5-100U/101U/115U Programmable Logic Controllers

The 6ES5955-3NF41 is a battery-backed RAM memory module designed to preserve:
✔ User programs
✔ Data blocks
✔ Process variables during power outages

Key Technical Specifications

Memory Configuration:

• Capacity: 32 KB (typical for S5-115U)

• Type: CMOS RAM with battery backup

• Data Retention: ≥1 year with fresh battery

• Battery Type: 3.6V Lithium (non-rechargeable)

Electrical Characteristics:

• Operating Voltage: 5V DC (via backplane)

• Battery Current: <50 μA (standby)

• Temperature Range: 0°C to +60°C

Physical Dimensions:

• Module Size: Single-slot (fits all S5 racks)

• Weight: 180g

Compatibility & Usage

Supported Systems:

• S5-100U (6ES5100-8MA**)

• S5-101U (6ES5101-8MA**)

• S5-115U (6ES5115-8MA**)

Installation Procedure:

1. Power off PLC rack

2. Insert module into any free slot

3. Connect battery plug

4. Initialize memory via STEP 5

Battery Maintenance

⚠ Critical Notes:

• Battery Life: 2-5 years (depends on ambient temp)

• Replacement Part: 6ES5955-3NF00 (battery only)

• Low Battery Indication: LED flashes red

Replacement Steps:

1. Maintain power to PLC during change

2. Complete within 30 seconds to prevent data loss

Modern Alternatives

Migration Path to S7 Systems:

Ordering Information

Current Status:

• Discontinued (last order date: 2007)

• Replacement Options:

  • Refurbished units available

  • Flash memory upgrades

Troubleshooting Guide

Common Issues:

• Data Corruption: Replace battery immediately

• Unrecognized Module: Clean edge connectors

• Write Errors: Verify memory permissions in STEP 5

Technical Documentation

📄 Certifications:

• EN 61131-2 (PLC standards)

• UL 508 (Industrial control)

🔧 Software Requirements:

• STEP 5 V7.1+ for configuration

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