Quick Sizing & Sourcing Snapshot

• Manufacturer: GE Fanuc (Emerson Automation)
• Part Number: IC697CMM742
• System Platform: GE Series 90-70 PLC
• Hardware Type: CMM742 Ethernet Interface Module (Type 2)
• Architectural Role: Occupies a single VME slot in the 90-70 CPU rack, acting as the TCP/IP gateway for SRTP programming, EGD data exchange, and Modbus TCP communication between the PLC and the plant network.
• Key Specifications: Ports: 10Base-T (RJ45), 10Base2 (BNC), AUI (15-pin); Power: 5V DC @ 2A / 12V DC @ 0.5A; Protocols: SRTP, EGD, Modbus TCP.

System Architecture & Operational Principle

The ​ is a dedicated communications co-processor that plugs into the VME backplane of a Series 90-70 rack, typically adjacent to the CPU (e.g., IC697CPU780). It does not pass through the CPU for data transfer; instead, it arbitrates the VME bus independently to read/write %R, %I, and %Q references directly from memory, freeing the main CPU from network interrupt overhead.

In the topology, this module sits at the interface between Level 2 (Cell Control) and Level 3 (Site Management). It connects via its front-facing ports to the plant Ethernet switch. The “Type 2” designation indicates it supports the full TCP/IP stack, including GE’s SRTP (Service Request Transport Protocol) for programming and HMI/SCADA reads, and EGD (Ethernet Global Data) for high-speed, multicast peer-to-peer data sharing between multiple 90-70 or RX3i controllers. It auto-negotiates which physical port (RJ45, BNC, or AUI) is active, but only one can be used at a time. Configuration is done via the PLC programming software (Proficy Machine Edition or Logicmaster), where you assign the IP address, subnet, gateway, and define the EGD exchanges. The module stores its configuration in non-volatile RAM, so it retains the IP address even if the PLC program is wiped, though it must be re-downloaded if the rack loses power completely without a battery (though the CMM has its own backup mechanism usually).

Core Technical Specifications

• Module Type: (Ethernet Interface, Type 2)
• Network Ports: 1 x 10Base-T (RJ-45), 1 x 10Base2 (BNC), 1 x AUI (15-pin D-Sub)
• Serial Ports: 1 x RS-232 (RJ-11, Station Manager), 1 x RS-485 (15-pin D-Sub, Firmware Load)
• Data Rate: 10 Mbps (IEEE 802.3 CSMA/CD)
• Supported Protocols: SRTP, EGD (Ethernet Global Data), Modbus TCP (Server/Client), TCP/UDP
• Backplane Power: +5 V DC @ 2.0 A (Max), +12 V DC @ 0.5 A (Max)
• Diagnostics: 4 LEDs (Module OK, LAN Online, Serial Active, Status OK)
• Configuration: Via Proficy Machine Edition / Logicmaster (IP, EGD, Modbus mapping)
• Memory: 1 MB (Typical, for buffering and configuration)
• Environment: 0°C to +60°C (32°F to 140°F), 5-95% RH (Non-condensing)
• Physical: Single VME slot width, approx 9.2 x 6.3 inches