Allen-Bradley 1794-IF2XOF2I Flex 2-In/2-Out Analog I/O – DIN-Rail, Hot-Swappable, 24 V DC

Product Overview

The Allen-Bradley 1794-IF2XOF2I​ is a Series A analog combination module from Rockwell Automation’s 1794 FLEX I/O platform, and it solves a very specific packaging problem: how to close a small analog control loop without giving up two full-width rack slots to a separate input card and output card. The module provides two galvanically isolated analog inputs and two galvanically isolated analog outputs in a single terminal-base footprint, so a pressure transmitter and a temperature transmitter can feed directly into the same block that drives a proportional valve and a VFD reference. That 2-in / 2-out symmetry is deliberate — it matches the shape of a single-loop PID, a skid-mounted recipe station, or a small machine axis far better than a sixteen-channel monolith does.

Signal flexibility is where the 1794-IF2XOF2I​ earns its keep. Every channel is independently software-configurable, so channel 0 can read a 4–20 mA two-wire pressure transmitter while channel 1 takes a ±10 V load-cell signal, and the two outputs can simultaneously hold a 0–10 V drive speed reference and a 4–20 mA valve positioner command. The analog front end uses sigma-delta conversion at up to 1200 Hz per input channel, with a 16-bit result (15 bits plus sign on the output side), and the module ships with 150 Hz, 300 Hz and 600 Hz factory-calibrated filter points that need no recalibration when you switch conversion rates. Four data formats — signed two’s complement, unsigned two’s complement, binary and offset binary — let the engineer match the module’s raw word to the controller’s existing scaling rather than rewriting the whole data table.

Architecturally, the Allen-Bradley 1794-IF2XOF2I​ is a block-transfer device riding the FlexBus. A 1794-ASB, 1794-ACNR15, 1794-AENTR or 1794-ADN adapter owns the network conversation, and the controller moves input words, output words and configuration words to and from the module with BTW/BTR semantics under Logix, or as a native Add-On Profile assembly on newer Studio 5000 systems. The isolation barrier is rated at 120 V AC continuous between channels and between the field side and the backplane, which is the practical detail that keeps a grounded transmitter in a distant motor room from poisoning the reference of a valve thirty metres away. For a mature product that Rockwell lists as active but deep into its lifecycle, that combination of density, isolation and software scaling is exactly why panels still get designed around it.

Technical Specifications