Description
Product Overview
GE Fanuc IC687BEM731 is a dedicated Genius Bus Controller module designed to connect GE PLC control platforms with distributed Genius communication networks. Installed in a Series 90-70 or PACSystems RX7i rack, the module manages data exchange between the host PLC and Genius field devices, allowing remote I/O blocks and intelligent devices to communicate with the controller through a single Genius bus channel.
The GE Fanuc IC687BEM731 operates as a communication interface rather than a processor or I/O module. It does not execute application logic, store PLC programs, or directly control field outputs. Instead, it handles Genius network communication functions, including I/O data exchange, diagnostics, datagrams, and Global Data communication between connected devices.
Within a typical architecture, the communication path is:
PLC CPU → IC687BEM731 Genius Bus Controller → Genius Bus Network → Remote I/O Blocks / Field Devices
The IC687BEM731 supports Genius networks containing multiple devices, including Genius I/O blocks, Series 90-70 remote drops, VersaMax I/O stations, Field Control stations, and other controllers capable of Genius communication. This makes it valuable in older distributed control installations where remote I/O networks remain operational and replacement of the entire control platform is not practical.
For maintenance engineers, the condition of the Genius Bus Controller is only one part of network troubleshooting. Communication failures can also originate from bus wiring, termination, device addressing, network loading, or faulty remote blocks. Before replacing an IC687BEM731, verify Genius bus diagnostics, device configuration, and physical network conditions.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | GE Fanuc / Emerson |
| Model | IC687BEM731 |
| Product Type | Genius Bus Controller |
| PLC Platform | Series 90-70 / PACSystems RX7i |
| Communication Protocol | Genius I/O Bus |
| Channels | 1 Genius Bus channel |
| Supported Devices | Up to 32 Genius devices |
| Bus Speed | 153.6 / 38.4 / 6.8 kbaud selectable |
| Backplane Voltage | 5 VDC |
| Backplane Current Consumption | 1.3 A |
| Slot Requirement | Single rack slot |
| Serial Interface | Handheld Monitor Port |
| Communication Functions | I/O data, Datagrams, Global Data |
| Redundancy Support | Supported in compatible systems |
| Operating Temperature | 0°C to 60°C |
| Mounting Location | RX7i or Series 90-70 rack |
Specifications are based on GE Fanuc technical references, which identify the module as a single-slot Genius Bus Controller with one channel, 5 VDC backplane supply, and 1.3 A current requirement.
Main Features and Advantages
IC687BEM731
Genius Network Communication Interface
The main purpose of is to provide a communication bridge between the PLC controller and Genius field networks.
Typical connected devices include:
- Genius I/O blocks
- Remote I/O drops
- VersaMax stations
- Field Control modules
- Other Genius-compatible PLC systems
This allows control systems to distribute I/O closer to field equipment while maintaining communication with the central PLC rack.
Support for Distributed I/O Architectures
The Genius network was widely used in industrial systems requiring remote I/O installation.
Typical advantages include:
- Reduced field wiring distance
- Centralized PLC control
- Remote signal acquisition
- Distributed cabinet layouts
The remains relevant in facilities maintaining legacy GE control systems.
Diagnostic and Monitoring Functions
The module supports Genius communication diagnostics, helping engineers identify:
- Network communication faults
- Device configuration issues
- Bus errors
- Remote I/O problems
The built-in handheld monitor interface provides an additional service connection for commissioning and troubleshooting.
Compatibility With Legacy GE Control Platforms
The supports both Series 90-70 and PACSystems RX7i environments, making it useful for migration projects and long-life industrial installations.
Common industries maintaining these systems include:
- Power generation
- Water treatment
- Manufacturing
- Process plants
- Material handling
Single-Slot Rack Installation
The module occupies one PLC rack slot, allowing integration into existing VME-style GE control racks without requiring additional chassis space.
Application Scenarios
Distributed Manufacturing Control
Used for connecting remote sensors and actuators through Genius I/O networks.
Utility Automation
Common in older:
- Water treatment systems
- Power distribution control
- Plant utility systems
Process Automation
Applications include:
- Chemical processing
- Production lines
- Batch control systems
Legacy PLC Migration Projects
The can help maintain existing Genius networks during phased controller upgrades.
Related Components
| Model | Function |
|---|---|
| IC697BEM731 | Series 90-70 Genius Bus Controller |
| IC687BEM733 | Related Genius communication module |
| IC693BEM331 | Series 90-30 Genius Bus Controller |
| IC200GBI001 | VersaMax Genius Network Interface |
| IC697CPUxxx | Series 90-70 CPU modules |
| IC695 CPU Modules | PACSystems RX7i controller modules |
Engineer’s Guide: Field Pitfalls
⚠️ Do Not Confuse With a Remote I/O Module
The is a bus communication controller.
It does not provide:
- Digital input channels
- Digital output channels
- Analog input conversion
- Analog output conversion
Remote I/O devices connected to the Genius network perform those functions.
⚠️ Check Genius Bus Wiring Before Replacing the Module
Common Genius network faults include:
- Incorrect termination resistance
- Damaged twisted-pair cable
- Grounding problems
- Incorrect device numbers
- Excessive bus length
A failed communication alarm does not always indicate a defective controller.
⚠️ Verify Device Address Configuration
Genius networks depend on correct device addressing.
Before replacement, record:
- Bus controller address
- Remote device addresses
- Network baud rate
- Genius configuration parameters
⚠️ Confirm RX7i / Series 90-70 Compatibility
Although the module supports both platforms, verify:
- CPU model
- Rack type
- Firmware revision
- Programming software version
Older Genius modules may require specific firmware levels for newer RX7i installations.
⚠️ Refurbished Testing Requirements
A proper evaluation should include:
- Visual PCB inspection
- Backplane power test
- Genius communication test
- Handheld monitor port test
- Network device simulation
- LED diagnostic verification
- Configuration verification
A simple power-up test does not confirm Genius network operation.
Frequently Asked Questions
What is GE Fanuc ?
It is a Genius Bus Controller module used to connect Series 90-70 and RX7i PLC systems with Genius communication networks.
Is a CPU module?
No. It is a communication interface module.
How many Genius devices can it support?
It can communicate with up to 32 devices on a Genius bus segment.
What PLC systems use ?
It is used with GE Series 90-70 and PACSystems RX7i platforms.
