The Allen-Bradley 1756-IG16, also cataloged as the 1756-IG16 Digital DC Input Module, operates as a dedicated hardware component for 5 VDC TTL discrete signal acquisition within ControlLogix system architectures.

Product Nomenclature & Circuit Configuration

• 1756: ControlLogix modular chassis backplane mounting platform.

• IG: Low-voltage TTL source digital DC input hardware topology.

• 16: 16-point discrete field signal channel allocation organized into two distinct groups of 8 points per common.

Electrical & Physical Specifications

Network Determinism & System Throughput

The module processes low-voltage TTL logic transitions across local and remote chassis racks while maintaining high-efficiency backplane bus communication velocity across EtherNet/IP deterministic networks. High-speed input filtering enables precise signal validation and I/O density scaling without overloading controller firmware flash compatibility or backplane scan cycles.

Shipping Package Content

• 1 x Allen-Bradley 1756-IG16 Digital DC Input Module Assembly

Wiring & Enclosure Installation Mechanics

• Align module rear card guides with the designated slot in the 1756 chassis until top and bottom latches snap securely.

• Wire field signal leads to a compatible Removable Terminal Block (RTB) or 1756 wiring interface module.

• Secure all TTL source input leads and ensure separate signal routing from high-voltage AC lines.

• Ground the chassis frame to main panel copper ground buses via low-impedance grounding straps.

Frequently Asked Questions

• What signal voltage level is compatible with the 1756-IG16 input module?

  The module interfaces exclusively with 5 VDC TTL sourcing signal logic across an operating window of 4.5 to 5.5 VDC.

• How are the 16 input channels logically grouped across internal commons?

  The 16 discrete input channels are divided into two isolated groups, allocating 8 points per common terminal.

• What current load does the module draw from the 5 VDC backplane rail?

  The unit draws 110 mA current from the chassis backplane 5 VDC supply during standard operation.

• What is the total signal response time for a channel state transition?

  Hardware input delay is 0.25 ms, which is added to the user-configured digital filter time in software.

• What is the maximum off-state current limit for field sensor inputs?

  Field device off-state leakage must not exceed 4.1 mA to guarantee a reliable OFF state recognition.

• Can the 1756-IG16 module be inserted into a ControlLogix rack under power?

  Yes, the module supports Removal and Insertion Under Power (RIUP) without causing chassis bus disruption.

• What is the maximum power dissipation rating for cabinet heat load calculations?

  The module exhibits a maximum power dissipation of 1.4 W when operating at an ambient 60 deg C limit.

• Does the module require a specific Removable Terminal Block for field connections?

  Yes, field wiring connects via a standard 20-pin RTB assembly such as the 1756-TBCH or 1756-TBNH.