Eaton 2D78559G01 Digital Input Module

The Eaton 2D78559G01 is a versatile digital input expansion module compatible with Eaton D series programmable logic controllers (PLCs). It adds 16 discrete input points to a control system, allowing the PLC to monitor the status of sensors, switches, pushbuttons, and other 24 VDC field devices. Each input is optically isolated from the backplane, ensuring reliable operation in electrically noisy industrial environments.

Key Features

• 16 digital inputs (24 VDC, sink/source selectable)

• Opto‑isolation: 1500 VAC between field and logic

• Input current: typical 7 mA at 24 VDC

• High‑speed counter capability (up to 10 kHz) on selected channels

• LED status indicators per channel for easy diagnostics

• Removable terminal block for quick wiring replacement

• Compatible with D series backplanes (D50, D100, etc.)

Technical Specifications

Wiring and Installation

The module connects to the PLC backplane via a gold‑plated edge connector, ensuring reliable electrical contact. The front‑mounted terminal block accepts wires up to 1.5 mm² (AWG 16) and is keyed to prevent incorrect insertion. All input circuits are protected against reverse polarity and transient surges. The module can be installed in any I/O slot of a D series rack and is hot‑swappable in most systems (check controller compatibility).

Applications

• Discrete sensor monitoring (proximity, limit switches, photoelectric)

• Pushbutton and selector switch interfaces

• Conveyor belt jam detection

• Packaging machine registration inputs

• Safety interlock monitoring (when used with proper safety PLC)

Configuration and Diagnostics

The 2D78559G01 is automatically recognized by the PLC programming software (e.g., EasySoft, CODESYS). Input filters, counters, and interrupt settings can be configured per channel. The green LED per input lights when the corresponding signal is active, simplifying troubleshooting. A module status LED indicates communication with the backplane.

With its robust design and flexible features, the Eaton 2D78559G01 is a reliable choice for expanding I/O capacity in small to medium automation systems, helping to reduce wiring and improve system modularity.