What are the GE Fanuc?
(Emerson) communication protocols?

GE Fanuc Automation — a joint venture between GE and Fanuc Ltd. of Japan, producing the Series 90-30, Series 90-70, Series Five, Series Six, and GE Micro PLC families under the GE Fanuc brand.

GE Fanuc Intelligent Platforms — the brand under which PACSystems RX3i, RX7i, and VersaMax were introduced. The joint venture structure was dissolved and GE took full ownership.

GE Intelligent Platforms — rebranded without the Fanuc name. The PACSystems and Series 90 families continued under this banner, with Proficy ME as the programming environment.

Emerson Automation Solutions — GE's industrial automation division was acquired by Emerson Electric. Hardware models and protocols are unchanged; the brand is now Emerson. TOP Server continues to refer to this family as the "GE Suite" to reflect the installed base naming.

SRTP (Service Request Transport Protocol) is GE's proprietary TCP/IP-based Ethernet protocol for PLC communication. It is the primary connectivity method for all GE/Emerson controllers with Ethernet capability — Series 90-30, Series 90-70, PACSystems RX3i and RX7i, VersaMax, and Horner OCS. SRTP uses GE's typed memory area addressing (I, Q, G, M, T, S, R, AI, AQ) for the classic 90-series families. For PACSystems RX3i and RX7i, the GE Ethernet driver also supports Symbolic Variable access — reading and writing variables by their programmer-defined names from VersaPro, Logic Developer, or Proficy ME. Tag import from these programming packages is fully supported, including 2-D tag structures and arrays up to 2,048 bytes.

Ethernet Global Data (EGD) is GE's proprietary peer-to-peer data sharing protocol. Unlike SRTP's request-response model, EGD uses a publish-subscribe pattern: controllers configured as EGD producers broadcast data exchanges at a defined interval using UDP (Unicast or Multicast), and consumers — including TOP Server — subscribe to those exchanges and receive data when it is published. This makes EGD well-suited for high-frequency data exchange and controller-to-controller communication. TOP Server's EGD driver can act as both a consumer (receiving EGD data from controllers) and a producer (publishing data from any PC to EGD subscribers), effectively turning the TOP Server machine into a first-class EGD node on the network.

SNP (Serial Natural Protocol) is GE's standard serial communication protocol, accessed via the RS-422 programming port on Series 90-30, Series 90-70, and GE Micro controllers. SNP supports the same memory area addressing (I, Q, G, M, T, S, R, AI, AQ) as SRTP Ethernet, making it straightforward to migrate a configuration from serial to Ethernet when network infrastructure is added. Data can be transferred in arrays up to 64 elements. Like the Ethernet driver, SNP supports tag import from VersaPro, Logic Developer, and Proficy ME, allowing the tag database from the programming environment to be imported directly rather than manually re-entered. Supports Communication Serialization for ordered request handling.

SNPX is an extended version of the SNP protocol that adds additional capabilities for Series 90 controllers. While SNP covers the standard programming port communication requirements, SNPX provides enhanced functionality for applications that require access to extended memory areas or advanced communication features not available in the base SNP specification. SNPX runs over the same RS-422 physical interface as SNP and uses a compatible addressing model, but with expanded command support. The SNPX driver includes the same VersaPro, Logic Developer, and Proficy ME tag import capability as the SNP and Ethernet drivers.

CCM (Computer Communication Module) is GE's legacy serial protocol, used by the oldest GE PLC families: the Series Five, Series Six, and Series Six CCM2. These controllers predate the Series 90 platform and use a fundamentally different communication interface — the CCM serial port — rather than the RS-422 SNP port. CCM is the connectivity path for plants that have Series Five or Six controllers still in operation, which is not uncommon in heavy industrial environments where equipment replacement requires long validation and approval cycles. The CCM driver also supports Ethernet Encapsulation via serial-to-Ethernet converters for modernizing CCM-connected installations.

The primary Ethernet driver for the GE/Emerson installed base, connecting to all Ethernet-capable GE controllers using the SRTP protocol over TCP/IP. Supports the full memory area set: %I (inputs), %Q (outputs), %G (global data), %M (internal coils), %T (temporary), %S (system status), %R (registers), %AI (analog inputs), and %AQ (analog outputs). Also supports %I and %P program variables and a comprehensive set of system parameters. For PACSystems RX3i and RX7i, additionally supports symbolic variable access — reading and writing programmer-defined named variables by tag name, with bit-level access within symbolic variables and read/write support when OEM Protection is enabled. Automatic Tag Database Generation from VersaPro, Logic Developer, or Proficy ME export files, including 2-D tag structures. Enhanced request blocking reads multiple memory blocks within a single SRTP request for maximum throughput. Array transfers up to 2,048 bytes.

Implements the GE Ethernet Global Data publish-subscribe protocol, supporting both Consumer (receiving EGD exchanges from GE controllers) and Producer (publishing EGD data to GE devices and other EGD consumers) connection modes. Supports both Unicast UDP (direct point-to-point data exchange with a specific IP address) and Multicast UDP (data broadcast to a multicast group address, receivable by all subscribed devices on the network segment). When operating as a Producer, the TOP Server machine itself becomes an EGD node — any PC running TOP Server can publish data to GE controllers and other EGD consumers. Consumer exchanges are configured by specifying the producer device IP, Exchange ID, and data layout; Producer exchanges are configured by specifying the consumer IP(s) or multicast group and the data to publish. Automatic Tag Database Generation via CSV import for efficient exchange configuration.

Connects to Series 90-30, Series 90-70, and GE Micro controllers via their RS-422 programming port using the SNP serial protocol. Uses the same memory area addressing model as the GE Ethernet driver (%I, %Q, %G, %M, %T, %S, %R, %AI, %AQ) plus program variables (%I and %P), making it straightforward to mirror a configuration between the serial and Ethernet drivers as network infrastructure is added to a plant. Full data type support including DWord (UINT). Supports array transfers up to 64 elements per request. Tag Database Generation from VersaPro, Logic Developer, or Proficy ME import files with 2-D tag support — the same import file used for the Ethernet driver works here. Communication Serialization provides ordered request sequencing for multi-device channels. Ethernet Encapsulation is supported for installations using serial-to-Ethernet converters.

The extended SNP protocol driver for Series 90 controllers that require SNPX's expanded command set and memory area access beyond what standard SNP provides. SNPX runs over the same RS-422 programming port physical interface as SNP but provides additional commands for accessing extended memory areas and advanced controller functions not covered in the base SNP specification. Like the SNP driver, SNPX supports the full VersaPro, Logic Developer, and Proficy ME tag import workflow and Ethernet Encapsulation for serial-to-Ethernet converter installations. Use SNPX when your Series 90 controller documentation specifies SNPX for external HMI/SCADA connections or when the SNP driver cannot access specific memory areas needed by your application.

Connects to GE's oldest PLC families — Series Five, Series Six, and Series Six CCM2 — using the CCM serial protocol via the controller's dedicated CCM communication port. These controllers use a different communication hardware interface than the RS-422 SNP/SNPX port, and the CCM protocol itself has a different command structure than SNP. CCM is the only connectivity path for Series Five and Series Six hardware; there is no Ethernet option for these platforms. Ethernet Encapsulation is supported for CCM, allowing a serial-to-Ethernet converter at the controller to bridge CCM traffic over TCP/IP — the recommended approach for modernizing Series Five and Six connectivity without requiring a direct serial cable from the TOP Server machine to the PLC. For plants with Series Five or Six controllers running compliance-critical applications, the CCM driver provides the path to bring that legacy data into OPC historians and modern analytics platforms.