Product Overview
The SIEMENS 6ES5318-8MA12 is a Connection 318 interface module belonging to the IM 318 family of the SIMATIC S5 series, engineered by Siemens to serve as the critical communications bridge between SIMATIC S5 central controllers and ET 100U distributed I/O stations. As the IM318 CC variant specifically designed for use in the ET 100U with cable connector, the SIEMENS 6ES5318-8MA12 enables SIMATIC S5-115U, S5-135U, and S5-155U programmable controllers to extend their I/O capacity across physically distributed machine cabinets and field enclosures. The SIEMENS 6ES5318-8MA12 operates on the SINEC L1 fieldbus—a dedicated S5 architecture bus distinct from PROFIBUS DP—providing robust, deterministic communication tailored for the harsh electrical environments characteristic of heavy industrial plants.
Positioned as a CC (Central Controller) interface module, the SIEMENS 6ES5318-8MA12 resides in the S5 central rack and manages the bus signals transmitted to remote ET 100U stations. A single SIEMENS 6ES5318-8MA12 can connect up to 3 expansion racks, with a maximum communication distance of 600 meters (extending to 1000 meters with shielded twisted-pair cable per technical documentation), enabling distributed I/O layouts that dramatically reduce wiring costs and sensor/actuator cable runs. The module draws approximately 1.5W of power directly from the S5 backplane bus, eliminating the need for separate external 24V DC supply and simplifying cabinet integration. Built to Siemens’ legendary SIMATIC S5 quality standards, the SIEMENS 6ES5318-8MA12 carries an IP20 protection rating and operates reliably across a -25°C to +60°C temperature range, making it suitable for deployment in control cabinets worldwide.
It is critically important to note that the SIEMENS 6ES5318-8MA12 is an ET 100U interface module that cannot be used in S7 systems—it is exclusively designed for SIMATIC S5 architecture. Although Siemens has long discontinued the SIMATIC S5 product line, the SIEMENS 6ES5318-8MA12 remains an absolutely mission-critical spare part for thousands of industrial facilities globally that continue to rely on S5 + ET 100U distributed I/O architectures for their daily operations. For plant engineers managing legacy S5 installations, the SIEMENS 6ES5318-8MA12 is not merely a component; it is the lifeline that sustains operational productivity, offering a cost-effective alternative to full system migration while preserving decades of validated control logic and mechanical integration.
Technical Specifications
| Parameter | Value |
|---|---|
| Product Model | SIEMENS 6ES5318-8MA12 |
| Manufacturer | Siemens AG |
| Product Type | SIMATIC S5 IM 318 CC Connection Interface Module |
| Module Designation | IM318 CC Interface Module for ET 100U with Cable Connector |
| System Compatibility | SIMATIC S5-115U, S5-135U, S5-155U |
| Target I/O System | ET 100U Distributed I/O Stations |
| Communication Bus | SINEC L1 Fieldbus (dedicated S5 extension bus) |
| Max Data Transfer Rate | 187.5 kbit/s |
| Max Expansion Racks | 3 remote ET 100U racks per module |
| Max Communication Distance | 600 m (up to 1000 m with shielded twisted-pair) |
| Transmission Medium | Shielded twisted-pair (SINEC L1 standard cable) |
| Power Supply | 5V DC from S5 backplane bus (no external 24V required) |
| Power Consumption | ~1.5 W |
| Electrical Isolation | Bus signal isolation between central rack and expansion link |
| Operating Temperature | -25°C to +60°C |
| Storage Temperature | -40°C to +85°C |
| Protection Rating | IP20 (for installation in module rack/cabinet) |
| Mounting | Standard SIMATIC S5 rack slot |
| Approximate Weight | 480 g |
| Diagnostic Features | Front-panel LED status indicators for power and bus communication |
| Lifecycle Status | Discontinued by manufacturer; available as new surplus / refurbished spare part |
| Important Note | Not usable in S7 systems; exclusively for SIMATIC S5 architecture |