Siemens 6ES5700-8FA11 | SIMATIC S5 Backplane Bus Module

The Siemens 6ES5700-8FA11 provides the internal communication backbone for SIMATIC S5 racks. This passive backplane board distributes power and data signals to all plugged modules. You can install it inside standard 6U and 9U S5 mounting frames. It carries the CPU bus, I/O bus, and 5V DC power rails simultaneously. Consequently, this module forms the foundation of any working S5 automation system.

Technical Specifications Overview

Parameter	Detailed Specification
Model	Siemens 6ES5700-8FA11
Category	SIMATIC S5 Passive Backplane / Bus Module
Number of Slots	8 (for S5 modules in single rack)
Bus Type	Parallel backplane (TTL level signals)
Voltage Rails	5V DC, 24V DC (internal), 24V DC (external pass-through)
Maximum Current (5V)	20 A (shared across all slots)
Maximum Current (24V)	4 A (for internal I/O supply)
Connector Type	64-pin DIN 41612 (per slot)
Dimensions (approx.)	290 mm x 260 mm x 2 mm (for 8-slot frame)
Weight	0.65 kg (650 grams)
Material	Epoxy-coated FR4 PCB with gold-plated contacts
Energy Storage	None (passive design, no capacitors)
Operating Temperature	0°C to 60°C

Functional Features and Backplane Capabilities

The Siemens 6ES5700-8FA11 requires no active components or external configuration. You simply mount it inside the compatible S5 rack frame. It provides precise slot-to-slot signal routing for reliable communication. Furthermore, the bus module includes dedicated traces for address, data, and control lines.

This backplane separates the I/O bus from the CPU bus electrically. Consequently, you can mix different module types without signal interference. The gold-plated DIN connectors resist corrosion for thousands of insertion cycles. Additionally, the board includes keying positions to prevent incorrect module installation.

Installation and Replacement Guidelines

First, remove all modules and power supply from your S5 rack. Next, unscrew the old backplane from the mounting frame. Then, position the Siemens 6ES5700-8FA11 carefully over the standoff posts. Finally, secure it using all original screws with even torque.

You must inspect each DIN connector for bent or damaged pins before installation. The backplane does not store any configuration data or user programs. Therefore, replacing it will not affect your PLC logic or parameters. Always use a ground strap to prevent electrostatic discharge during handling.

This bus module works perfectly for repairing damaged or corroded S5 racks. It fits all standard S5 housings including 6ES5700-8FA11 compatible frames. You can also use it to build custom rack configurations from spare parts. The passive design means zero maintenance after proper installation.