Features:
- Eight AC/DC discrete input points for a 1771 I/O chassis.
- Separate 120 V AC and 125 V DC nominal input specifications with defined state thresholds.
- Filtered, optically isolated inputs with individual field-voltage indicators.
1771-IA retains the installed eight-point input footprint in a 1771 rack. That matters when a PLC-5 cabinet must keep its existing I/O layout during service rather than move the field wiring to a new platform.
The specified AC and DC input bands are distinct. For field devices that do not switch cleanly to zero, the off-state limit gives a practical boundary for deciding whether the signal is low enough for this card.
The removable field wiring arm and front indicators make each point accessible at the cabinet. The indicators show field-side voltage, while the controller input image remains the separate test of the logic state.
1771-IA | Manufacturer: Allen-Bradley | Product Type: 8 Point Digital Input Module. Apter Power supports exact-model document review, quotation and sourcing for this discontinued module.
Allen-Bradley 1771-IA 8 Point Digital Input Module Manuals,Datasheets,Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
- AC on state: A Series C point needs 87–138 V AC at the input to sit within its published high-state band.
- DC on state: The corresponding 125 V DC circuit uses the separate 97–138 V DC band; AC limits are not the test for that channel.
- Open contact: The stated off-state ceilings, 46 V AC peak or 57 V DC, help interpret residual voltage at a released input.
- Electronic sensor: An AC proximity output should have less than 2.8 mA off-state leakage for the specified Series C interface.
- Field wiring: The specified 1771-WA arm carries the input terminations; matching that arm to the cabinet point map preserves the intended circuit identities.
- Chassis location: The 1771 module uses slot keying, so the installed key pattern is part of the physical service record for this card.
- Backplane draw: Include the module’s 75 mA requirement in the 1771 rack supply calculation rather than using an empty slot as the only installation criterion.
- Operating ambient: The published 0–60 °C range sets the cabinet-temperature envelope for an energized 1771-IA.
- Stored spare: The -40–85 °C storage range applies before installation, separate from the narrower operating range.
- Condensation: The 5–95% relative-humidity rating is non-condensing; a wet enclosure is outside that stated condition.
- Heat load: Up to 10.7 W, or 36.5 BTU/h, is the listed dissipation to consider when evaluating cabinet heat.
- AC contact states: The eight inputs can bring 120 V-class switch or relay-contact states into a 1771 I/O rack.
- DC contact states: The same catalog number has a specified 125 V DC nominal input path for discrete field status signals.
- AC proximity outputs: Series C data provides an off-state leakage boundary for an electronic proximity device connected as an input.
- Installed PLC-5 systems: In a 1771 chassis, the module serves existing discrete-input points without changing the controller’s rack layout.