The Allen-Bradley 1772-LS, also cataloged as the 1772LS PLC-2/05 Processor Module, operates as a dedicated hardware component for program execution and digital I/O processing within Mini-PLC-2/05 controller platforms.

Model Identification & Configuration

The 1772-LS is a Mini-PLC-2/05 processor module designed for PLC-2 series control systems. The module provides processor execution, memory storage, and I/O scanning functions through the PLC chassis backplane. It contains 3K words of CMOS RAM and operates with external 120 VAC system power.

Hardware Specifications

PLC-2 Processor Architecture

The Allen-Bradley 1772-LS uses PLC-2 series processor architecture for sequential instruction execution, internal memory handling, and digital I/O control. The processor communicates with connected I/O modules through the chassis backplane and manages controller operating states through RUN, TEST, and PROG modes.

The module design reflects Allen-Bradley legacy PLC hardware structures. Firmware operation, I/O addressing, and chassis configuration are dependent on the original PLC-2 system design and are not compatible with newer ControlLogix or EtherNet/IP platforms.

Industrial Control Compatibility

The 1772-LS supports legacy PLC digital control applications through fixed I/O chassis communication. The processor module uses backplane bus communication methods rather than modern deterministic Ethernet networks.

The PLC-2 architecture requires correct processor slot placement, I/O module arrangement, and memory verification during maintenance replacement. Program retention depends on the installed CMOS RAM memory configuration.

Ordering Information

• 1 x Allen-Bradley 1772-LS PLC-2/05 Processor Module
• 1 x PLC-2 series processor hardware assembly
• 1 x Installed CMOS RAM memory system
• 1 x Module identification label
• 1 x Technical inspection record

Field Installation Guidelines

Processor Mounting

• Install the 1772-LS in the left-most slot position of the compatible I/O chassis.
• Confirm chassis alignment before insertion.
• Verify backplane connector condition before installation.

Power Connection

• Confirm the 120 VAC supply specification before energizing the system.
• Inspect power wiring and grounding connections according to the original PLC installation requirements.
• Do not remove or insert the processor module under energized conditions unless the chassis design permits hot insertion.

System Verification

• Confirm PLC-2 program memory status before operation.
• Check PROC RUN and FAULT indicators after startup.
• Verify I/O module configuration matches the existing control program.

Frequently Asked Questions

• What controller system uses the 1772-LS processor?

  The 1772-LS is a PLC-2/05 processor module designed for Allen-Bradley Mini-PLC-2 control systems.

• What type of memory is installed in the 1772-LS?

  The processor uses CMOS RAM memory with a capacity of 3K words for PLC program storage.

• Does the 1772-LS include a power supply?

  No. The processor module requires a separate compatible system power supply arrangement.

• Where is the 1772-LS installed in the chassis?

  The module is installed in the left-most slot of the compatible PLC-2 I/O chassis.

• What operating modes are available on the processor?

  The module supports RUN, TEST, and PROG operating modes for controller execution and maintenance.

• How many I/O modules can the 1772-LS support?

  The processor supports connection with up to 6 I/O modules within the PLC-2/05 chassis configuration.

• Does the 1772-LS support EtherNet/IP communication?

  No. The module uses legacy PLC-2 backplane communication and does not include Ethernet interfaces.

• What indicators are available for diagnostics?

  The processor provides PROC RUN and FAULT indicators for basic operating status monitoring.