Configured for discrete status signal sensing in 1771 I/O chassis assemblies, the Allen-Bradley 1771-IG (1771IG Digital Input Module) provides direct physical/electrical execution.

Catalog Nomenclature & Hardware Variants

• 1771-IG: Standard 16-point discrete TTL digital input card engineered for Allen-Bradley 1771 chassis racks.
• 1771IG: Equivalent base assembly part number representing identical 16-point TTL digital input circuitry.

Electrical & Physical Specifications

Deterministic Network & Bus Integration

The assembly processes field contact state changes and leverages backplane bus communication velocity routines to transmit digitized status bits across the backplane bus. High channel density enables optimized I/O density scaling inside standard 1771 universal racks. The internal architecture maintains strict firmware flash compatibility with host PLC-5 controllers to prevent scan cycle delays or data buffer mismatches during execution.

Standard Package Items

• 1 x 1771-IG Digital Input Module Assembly
• 1 x Field Wiring Arm Alignment Keying Clip

Mechanical Installation & Wiring Guidelines

Chassis Insertion Steps

• Snap plastic keying bands into the chassis backplane edge connector at designated pin positions to enforce correct slot keying.
• Align top and bottom circuit board guides with chassis slots and slide the assembly inward until the rear connector seats into the backplane.

Wiring and Shielding Standards

• Route digital signal conductors using twisted-pair wiring to prevent electromagnetic cross-talk.
• Terminate signal drain wires to frame ground at a single panel connection point to avoid ground loops.
• Maintain a minimum separation of 30 cm between low-voltage TTL signal conduits and AC power cables.

Technical Operational FAQs

• What input voltage logic levels are supported by the 1771-IG?

  The module is designed to interface with 5 VDC TTL logic-level discrete signal sources across its 16 points.

• How much current does the 1771-IG draw from the chassis backplane?

  The module logic circuits draw a nominal current load of 0.3 A at 5 VDC from the 1771 chassis backplane supply.

• Is hot-swapping permitted while the 1771 chassis is powered?

  No. Disconnect backplane power before inserting or removing the card to prevent electrical damage to connector pins.

• What is the total digital point density of this input module?

  The 1771-IG module provides 16 discrete input channels for monitoring field device state conditions.

• What wire gauge size is compatible with the field wiring arm?

  The field wiring terminal block accepts solid or stranded copper wire sizes ranging from 14 AWG to 22 AWG.

• How does the module handle signal filtering for noise suppression?

  Internal RC filtering circuits condition input signals to prevent contact bounce transients from triggering false scans.

• Does the module require an external DC power supply for field inputs?

  Yes. Field inputs require a clean external 5 VDC supply reference matching TTL logic threshold requirements.

• What operating temperature envelope applies to this module?

  The card is specified for continuous operation in cabinet environments ranging from 0 to 60 deg C.