Product Overview

The Allen-Bradley 2085-IA8​ is an 8-point 120V AC digital input module belonging to Rockwell Automation’s 2085 expansion I/O family, purpose-built to extend the input capacity of Micro800-series controllers (Micro820, Micro830, Micro850, Micro870) via the CPU’s right-side proprietary expansion bus. While the Micro800 CPUs themselves carry a baseline of embedded I/O (e.g., the Micro850 2080-LC50-24QBB offers 14 DI / 10 relay DO embedded), many OEM machines and small-process skids need additional 120V AC sensing — contactors, overload aux contacts, tower-light dry contacts, float-switch 120V AC legs, door-interlock 120V AC — without stepping up to a CompactLogix or adding a separate 1769 I/O rack. The 2085-IA8​ fills that gap: eight independently wired 120V AC input channels, grouped as two groups of four with a common terminal per group, each channel accepting 79–132V AC at 47–63 Hz, configurable per group as sink or source by how the field common is wired. The module communicates back to the Micro800 CPU over the 2085 ribbon bus (tongue-and-groove mechanical, no tools beyond the release clip), and the I/O image maps automatically into the Micro800 %I memory space inside Connected Components Workbench (CCW) — no add-on profile, no EDS, no Studio 5000 license.Physically, the 2085-IA8​ is a slim 35 mm-wide DIN module (compatible with 35 mm symmetrical rail, also panel-mount via screw tabs), 110 mm high × ~75 mm deep, IP20 (cabinet required), with one green LED per channel (on = voltage present at terminal) plus a module-status green/red LED. Power for the 2085-IA8’s​ internal logic comes from the 2085 bus (draws from the Micro800 CPU’s 24V DC supply budget — check CPU’s 2085-bus power budget before stacking), while the 120V AC field power is externally supplied per group common. The 2085-IA8​ qualifies to -20 to +65 °C (wider than many compact modules), 25 G operating shock, 2 G vibration @ 10–500 Hz, and carries UL 508, CE, C-Tick, KC, and ABS Marine certifications — aligning with the Micro800 family’s industrial positioning. Lifecycle is Active​ (Rockwell current), origin Singapore/Malaysia depending on batch. Maximum expansion depth varies by CPU: Micro810 = 0 (no 2085 port), Micro820 = up to 2× 2085 modules, Micro830 = up to 5, Micro850/Micro870 = up to 8. So a fully loaded Micro870 can mix, say, two 2085-IA8​ (16× 120V AC in) + two 2085-OA8 (AC out) + two 2085-IB8 (24V DC in) + two 2085-OB8EP (protected DC out) = 8 modules, all scanned by the Micro870 CPU in one CCW project. For OEMs building small-to-mid machines on Micro800 that need 120V AC sensing without a larger platform, the 2085-IA8​ is the right-bus native answer.

Technical Specifications

Main Features and Advantages

120V AC Input Without Leaving the Micro800 EcosystemThe core proposition of the 2085-IA8​ is letting a Micro800-based machine sense 120V AC field devices natively. Many small machines have a mixed-voltage reality: the CPU runs 24V DC (embedded DI/DO), but the panel also has 120V AC contactor aux contacts, overload-relay NO/NC, 120V AC tower-light dry contacts, door-switch 120V AC legs, and float-switch 120V AC versions (common in North American building/pump panels). The 2085-IA8​ absorbs those without an interposing 24V DC relay layer or a separate 1769/5069 AC-input rack. Each channel is independent wiring (screw-clamp, 24–14 AWG), two groups of four with a common terminal per group — so group 1 can be sunk (common to 0V / L2) and group 2 sourced (common to 120V AC L1) if the field mix demands it, all on the same 2085-IA8.