The Allen-Bradley 1756-IB16D, also cataloged as the 1756-IB16D Digital Input Module, operates as a dedicated hardware component for 12-24 VDC sinking discrete diagnostic signal acquisition within ControlLogix system architectures.

Product Structure & Model Identification

• 1756: ControlLogix modular chassis backplane mounting platform.

• IB16: 16-point discrete DC input circuit design operating on 12-24 VDC sinking voltage levels.

• D: Integrated diagnostic capability providing open-wire field circuit detection and fault reporting.

Technical Parameters & Operational Limits

Deterministic Network Backplane Operations

The diagnostic input circuitry processes 10-30 VDC field signals while sustaining steady backplane bus communication velocity across EtherNet/IP deterministic networks. Channel diagnostic bit routines detect open field circuits directly at the terminal connection, maximizing I/O density scaling and maintaining firmware flash compatibility across local and remote chassis nodes.

Standard Delivery Content

• 1 x Allen-Bradley 1756-IB16D Diagnostic Digital Input Module

Field Mounting & Wiring Mechanics

• Seat the rear printed circuit board guides into the targeted chassis slot until mechanical latches fully lock.

• Connect DC power and input field wiring to a compatible Removable Terminal Block (RTB).

• Verify sensor wiring polarity complies with sinking input current requirements across all 16 channels.

• Route signal wires away from high-voltage motor cables to minimize electromagnetic interference.

Technical FAQ

• What primary diagnostic function does the 1756-IB16D module perform?

  The module continuously monitors field circuit wiring to detect and report open-wire conditions per point.

• What operating voltage range is supported on the input channels?

  Each channel operates across an input range of 10 to 30 VDC with a nominal rating of 12-24 VDC.

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

  The internal logic draws 150 mA current directly from the chassis 5 VDC backplane supply rail.

• What is the maximum allowed off-state leakage current per channel?

  Field device off-state leakage must remain below 1.5 mA per point to prevent false ON state reads.

• What is the minimum operating current required to trigger an ON state?

  The hardware input requires a minimum operating current of 2 mA at 10 VDC for input signal registration.

• Does this module support hot-swapping during active system operation?

  Yes, the module supports Removal and Insertion Under Power (RIUP) without disrupting chassis operation.

• What is the maximum power dissipation rating for thermal enclosure calculations?

  The maximum thermal output is rated at 5.8 W when operating under full load at 60 deg C ambient.

• What wiring interface block is used to connect field sensors?

  Field wiring interfaces through standard ControlLogix 20-pin or 36-pin RTB units like the 1756-TBCH.