Hardware Comparison: GE Fanuc Series 90-30 vs the Emerson GE RX3i

The GE Fanuc Series 90-30 PLC has been a reliable, modular automation solution for decades, introduced in 1991. It became a staple in industrial applications due to its versatility, ease of use, and support for numerous I/O and communication modules. In contrast, the Emerson GE RX3i Programmable Automation Controller (PAC) represents a more modern, scalable, and connected evolution, bridging legacy functionality with IIoT capabilities.

GE Fanuc Series 90-30

General Features:

• Modular PLC design with a variety of CPUs (entry, midrange, high-end)

• Over 100 I/O and specialty modules available

• Supports Ladder Logic and Sequential Function Chart (SFC)

• Online programming and diagnostics

• Four-level password security

• Compatible with various communication buses (Ethernet, Genius, DeviceNet, Profibus, etc.)

CPU Categories:

• Entry-Level: CPU311, CPU313, CPU323

  • Discrete I/O: 160–320

  • Analog I/O: 64 In / 32 Out

  • Memory: 6K–12K bytes

  • Serial Ports: 1

• Mid-Range: CPU331, CPU341

  • Discrete I/O: 1024

  • Analog I/O: Up to 1024 In / 256 Out

  • Memory: Not specified

  • Serial Ports: 1

• High-End: CPU350, CPU351, CPU352, CPU360, CPU363, CPU364

  • Discrete I/O: 4096

  • Analog I/O: 2048 In / 512 Out

  • Memory: 80K–246K bytes

  • Serial Ports: 3 (except 364 with Ethernet/TCP/IP)

  • Programming Languages: Ladder, SFC, and C

Communication Options:

• Genius Bus Controller

• World FIP

• Profibus

• Interbus

• LonWorks

• DeviceNet

• SDS

• Modbus RTU

Specialty Modules:

• High-speed counters

• SPC coprocessors

• Modems

• Stepper motor controllers

Emerson GE RX3i

Overview:

• Direct upgrade path from 90-30

• Designed for IIoT and connected factory environments

• Mounting and slot-compatible with 90-30 modules

• Supports incremental upgrade and hot-swap replacement

CPU Models:

• Standalone Controllers: CPE100, CPE115

  • User Memory: 1.0–1.5 MB

  • Ethernet Ports: 4

  • Serial Ports: 1

  • Supports PROFINET, Modbus TCP/IP, EGD, SRTP, and Serial RTU

• Mid-Range Controllers: CPE302, CPE305, CPE310

  • User Memory: 2–10 MB

  • Discrete I/O: Up to 32KB

  • Analog I/O: 32KB Words

  • Remote I/O Devices: 8 simplex

• High-End Controller: CPE330

  • User Memory: 64MB

  • Remote I/O: 64 simplex / 64 redundant

  • Serial and Ethernet communication as standard

• Advanced Controllers: CPE400, CPL410 (Linux OS)

  • User Memory: 64MB

  • Remote I/O: 32 simplex / 20 redundant

  • Ethernet Ports: 3 (2 switched)

Common RX3i Features:

• Support for Ladder, Function Block, Structured Text, and C

• 512 program blocks

• Online editing

• Configurable data and program memory

• Embedded serial and Ethernet communication

Communication Capabilities:

• Built-in PROFINET adaptors

• EtherNet/IP, Modbus TCP/IP

• Serial I/O: Modbus/RTU, ASCII

• Remote I/O: Simplex and Redundant

Modularity & Interchangeability:

• Same backplane dimensions and mounting as 90-30

• Direct plug-in compatibility with many 90-30 modules

• Incremental migration with minimal downtime

Benefits of RX3i Over 90-30

• IIoT Readiness: Native support for IIoT and cloud integration (GE IICS, Predix Cloud)

• Scalability: Up to 32KB I/O per controller vs. 90-30’s 4096 I/O limit

• Real-Time Communication: Through integrated PROFINET

• Lower Total Cost of Ownership: Phased upgrades reduce capital expenditure

Limitations of 90-30 vs. RX3i

• Not RoHS compliant

• Some 90-30 modules are not compatible with RX3i

• No built-in support for IIoT or cloud

• Lower I/O scalability and memory

Incompatible 90-30 Modules with RX3i (Examples):

• Some programmable coprocessor modules

• 10x 24V DC modules

• Communication control and Genius Bus modules

• Complicity system modules

Conclusion While the GE Fanuc Series 90-30 was a revolutionary PLC system for its time, the Emerson GE RX3i offers a future-proof solution designed for connected, high-performance applications. With backward compatibility and enhanced IIoT capabilities, the RX3i provides a seamless, cost-effective path for migrating legacy systems to modern architectures while preserving existing hardware investments.

For more information or help selecting the right drive, contact PLG Automation:Email: sales@plgautomation.comPhone: 800-906-9271