Allen-Bradley 1720-L002 PLC Logic Function Module

The Allen-Bradley 1720-L002, also cataloged as the 1720-L002 PLC Module, operates as a dedicated hardware component for direct logic gate execution within industrial PLC systems. Configured as an open-style mountable printed circuit board assembly, the unit provides hardware-level digital logic processing without onboard software execution layers.

Suffix Breakdown & Model Matrix

The model designation 1720-L002 follows standard early-generation Allen-Bradley logic module cataloging logic:

• 1720: Identifies the primary legacy PLC hardware series and rack/board interface platform.
• L002: Designates the specific functional circuit configuration implementing 2-input AND gate logic operations across 10 functional logic channels.

Hardware Specifications

Industrial Control & Backplane Communication Properties

As a specialized board-level execution unit within Allen-Bradley control architectures, the 1720-L002 incorporates hardware-level signal processing traits:

• Backplane Bus Communication Velocity: Implements direct bus connection traces for high-speed signal handshaking, transferring logic states across backplane bus structures with sub-millisecond propagation delay.
• Profinet / EtherNet/IP Deterministic Networks: Functions at the local sub-rack layer, executing hardware-level gate decisions before transmitting system statuses to higher-level deterministic networks via central processor gateway modules.
• Firmware Flash Compatibility: Utilizes pure hardwired semiconductor logic gates, eliminating firmware flash dependencies and ensuring consistent signal throughput regardless of system CPU software revisions.

Frequently Asked Questions

Q: How does the 1720-L002 process digital logic inputs?

A: The board features 10 discrete functional circuits, each operating as a physical 2-input AND gate, executing pure hardware logic states without software scan times.

Q: What mounting precautions must be taken for the open-style board assembly?

A: Because the module is an open-style printed circuit board assembly, it must be installed in a grounded, protective card cage or enclosure to prevent electrostatic discharge (ESD) and airborne contaminants from degrading board traces.

Field Installation Guidelines

Proper handling and installation procedures are mandatory to ensure reliable execution and preserve board components:

• Handling and ESD Protection: Always wear an anti-static wrist strap connected to a verified earth ground before removing the board from its conductive protective packaging. Touch board edges only; do not contact conductive traces or IC pins.
• Mechanical Mounting: Slide the module cleanly into the dedicated chassis guide rails. Firmly seat the edge card connector into the backplane socket to maintain low-resistance signal contacts before securing retention fasteners.
• Wiring and Signal Isolation: Keep signal wiring leads connected to the rack short and shielded. Route low-voltage logic signal lines away from high-voltage AC power lines and heavy motor cables to prevent capacitive noise coupling into input channels.