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Bulletin 1797 FLEX Ex I/O In-Cabinet Modular


Bulletin 1797 FLEX Ex™ Intrinsic Safety (IS) I/O couples the benefits of our FLEX™ I/O platform with IS technology. This lets you distribute I/O throughout hazardous areas with a single or redundant fiber or coax cable, virtually eliminating standalone IS barriers and isolators, enclosures, long wiring runs, and cable trays. FLEX Ex I/O communicates with your control system over a ControlNet™ network. It is compatible with standard FLEX I/O and communication modules for added flexibility in network choices and system configuration.

  • Overview
  • Products
  • Documentation
  • Resources


  • Installs into hazardous areas (Zone 1) without purged or explosion-proof enclosures
  • Provides a ControlNet-based solution in the hazardous area using ControlNet™ Ex products
  • Modular design lets you independently select the I/O, termination style and network interface
  • Assembles without tools—all components snap onto a DIN rail and plug together to form the I/O system
  • Mounts horizontally or vertically on a standard DIN rail
  • Removal and Insertion Under Power (RIUP) lets you replace modules and make connections in the hazardous area while the system is in operation
  • Simplified engineering drawings, documentation, and site certification speed commissioning


1797 FLEX Ex™ I/O Communication Interfaces

  • Provides the interface between the FLEX Ex I/O modules and backplane, and the ControlNet network
  • Snaps onto the DIN rail

1797 FLEX Ex I/O Terminal Bases

  • I/O module plugs into the terminal base
  • Provides terminal connection points for an I/O module
  • Snaps onto the DIN rail
  • Terminal bases plug into each other to form the system backplane

1797 FLEX Ex I/O Modules

  • Provides intrinsic safety I/O circuits
  • Plugs into a terminal base on the DIN rail
  • Connect a maximum of eight I/O modules in an assembly

1797 FLEX Ex Power Supplies

  • Two 120V AC or 24V DC options available for powering the FLEX Ex I/O system

1797 FLEX Ex I/O Accessories

  • Variety of products to enhance installation flexibility and to fill special termination needs
  • Select cables, taps, insulators, and products for hazardous location installations


  • FLEX Ex I/O modules are rated for installation in:
    • Class I Division 1 & 2, Groups A-D hazardous areas
    • North American Class I Zone 1 & 2, Groups IIC, IIB, & IIA hazardous areas
    • European Zones 1, 2, and 22
  • FLEX Ex I/O modules are rated for connection to:
    • Field devices located in Class I, II, or III, Groups A-G hazardous areas
    • Devices in Class II or III locations
    • Field devices located in North American Class I Zone 0, 1, & 2, Groups IIC, IIB, & IIA hazardous areas
    • Field devices located in European Zones 0, 1, 2, 21, and 22 hazardous areas
  • FLEX Ex power supplies are rated for use in Zones 1 and 22

Certifications apply when product is marked. See our Product Certification site for Declarations of Conformity, certificates and other certification details.

Communication Interfaces

Use the Bulletin 1797 FLEX Ex™ communication module and FLEX Ex I/O installed in the hazardous area to gather data at its origin and transport it to the safe area with minimal wiring. ControlNet™ Ex connectivity leverages the diagnostic capabilities and determinism of the ControlNet network for intrinsic safety (IS) applications. FLEX Ex is also compatible with standard FLEX™ I/O communication modules for connectivity to DeviceNet™, Universal Remote I/O, and EtherNet/IP™ networks.

I/O Modules

Bulletin 1797 FLEX Ex™ Intrinsic Safety (IS) I/O provides flexibility for your hazardous application. Use FLEX Ex I/O with a FLEX Ex communication module installed in the hazardous area to gather data at its origin and transport it to the safe area with minimal wiring. Advanced diagnostics provide real-time status for easier troubleshooting.

Power Supplies

Bulletin 1797 FLEX Ex™ power supplies provide power for the FLEX Ex ControlNet™ Ex network, communication adapter, I/O modules, fiber hub, and intrinsic safety (IS) field devices. No other power sources are needed to operate any components attached to the FLEX Ex system in the hazardous area. Power for valves, actuators, or transmitters comes from the FLEX Ex modules.

Terminal Bases

Bulletin 1797 FLEX Ex™ terminal bases snap onto the DIN rail to the right of the communication adapter module. The terminal bases provide terminal connection points for I/O wiring and plug together to form the backplane.


FLEX I/O and FLEX Ex I/O Selection Guide1794-SG002
FLEX Ex System Certification Reference Manual1797-RM001
ControlNet Ex Media System Planning and Installation ManualCNET-IN003
More 1797 FLEX Ex I/O publications in Literature LibraryAll Languages

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Product Certifications

See our Product Certification site for Declarations of Conformity, certificates and other certification details.

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Configuration & Selection Tools

Other Resources

  • Electronic Data Sheets — Find DeviceNet™, ControlNet™, EtherNet/IP™, and network-independent EDS files.
  • Sample HART RLL code
  • Knowledgebase — Visit our online resource for technical information, support chat and forums, software updates, and product safety advisories/notices.