Description

The IC687BEM742 is a high-performance Bus Extension Module developed by GE Fanuc (now part of Emerson’s automation portfolio) for the Series 90-70 PLC system. This specialized module serves as a critical infrastructure component that extends the backplane communication capabilities of the Series 90-70 platform, enabling the creation of distributed I/O systems across multiple racks. The primary function of the IC687BEM742 is to establish a high-speed, reliable connection between a primary Series 90-70 CPU rack and one or more remote expansion racks, significantly extending the physical and logical reach of the control system beyond the limitations of a single chassis.

As part of GE’s comprehensive Series 90-70 system architecture, the IC687BEM742 enables engineers to design sophisticated control systems with distributed I/O configurations while maintaining centralized processing power. This module facilitates seamless data exchange between the main CPU and remote I/O racks, ensuring deterministic performance and maintaining data integrity across extended distances. The IC687BEM742 is particularly valuable in large-scale industrial applications where I/O points are geographically dispersed, as it eliminates the need for excessive home-run wiring and allows for more flexible system layout while maintaining the processing power and reliability of the Series 90-70 platform.

Technical Specifications

Main Features and Advantages

The IC687BEM742 offers several advanced features that make it an essential component for expanding Series 90-70 systems. Its high-speed data transfer capability (2.5 Mbps) ensures minimal communication latency between the main CPU rack and remote expansion racks, maintaining system performance even with distributed I/O configurations. The module provides robust electrical isolation (1500V AC) between connected racks, protecting the main CPU and local I/O from electrical disturbances that might occur in remote locations. This isolation feature is particularly valuable in industrial environments where different areas of a facility may experience varying electrical conditions.

The IC687BEM742 supports automatic configuration and diagnostics, simplifying system setup and maintenance. LED status indicators provide immediate visual feedback on module operation, communication status, and any fault conditions, enabling quick troubleshooting. The module’s ability to support up to four remote expansion racks from a single module significantly reduces system cost and complexity compared to alternative distributed I/O solutions. The IC687BEM742 maintains data integrity through error checking and correction mechanisms, ensuring reliable operation in electrically noisy industrial environments. These features combine to make the IC687BEM742 a reliable and cost-effective solution for expanding Series 90-70 control systems.

Application Field

The IC687BEM742 finds extensive application in large-scale industrial automation systems where control requirements exceed the capacity of a single PLC rack or where I/O points are geographically dispersed. In automotive manufacturing plants, the IC687BEM742 is used to connect control racks across different sections of assembly lines, allowing centralized control of distributed processes. In water treatment facilities, the module enables expansion of control systems across multiple processing areas such as filtration, chemical treatment, and pumping stations, while maintaining centralized supervision and control.

The IC687BEM742 is particularly valuable in material handling systems, such as airport baggage handling or warehouse automation, where I/O points are spread over large areas but require coordinated control. In power generation facilities, the module helps distribute control capabilities to different areas of the plant while maintaining central oversight. The IC687BEM742 also serves well in food and beverage processing plants where hygiene requirements often necessitate locating control equipment away from processing areas. In all these applications, the IC687BEM742 provides the crucial link that enables flexible system architecture while maintaining the performance and reliability expected from Series 90-70 systems.

Related Products

IC697BEM743: An enhanced version of the bus extension module with extended distance capabilities

IC697CPU781: A Series 90-70 CPU module that serves as the main processor in systems using the IC687BEM742

IC694MDL645: A typical digital input module used in expansion racks connected via the IC687BEM742

IC693BEM331: A Genius bus controller module for alternative distributed I/O solutions

IC690ACC901: Cable assembly used for connecting expansion racks with the IC687BEM742

IC697PWR711: Power supply module for Series 90-70 expansion racks

IC697CHS781: Expansion chassis for creating remote racks connected via the IC687BEM742

Installation and Maintenance

Pre-installation preparation: Before installing the IC687BEM742, ensure all power to the Series 90-70 rack is completely disconnected. Verify rack compatibility and ensure adequate power supply capacity for the additional load presented by the module and any connected expansion racks. Plan the physical layout of the system, considering the maximum cable length limitations and environmental conditions. Have the appropriate cabling and connectors ready, and ensure proper grounding provisions are available at all rack locations.

Maintenance recommendations: The IC687BEM742 requires minimal routine maintenance but should be periodically inspected for signs of physical damage or connector corrosion. Monitor the module’s status LEDs during operation to ensure proper communication with expansion racks. Maintain clean connections and ensure proper ventilation around the module to prevent overheating. Keep a record of the system configuration and module settings for troubleshooting purposes. Regularly check cable integrity and connections, as these are the most common points of failure in expansion systems. For optimal performance, avoid running extension cables near sources of electrical noise such as motor drives or high-current wiring.