The Allen-Bradley 1772-LP3, also cataloged as the 1772-LP3 Processor Unit, operates as a dedicated hardware component for central logic processing and I/O scan execution within PLC-2/30 system racks.

Hardware Designation Breakdown

• 1772-LP3: Primary chassis-mount processor assembly for execution of industrial ladder logic and peripheral scan routines.

• 1772LP3: Alternate catalog string referencing identical internal logic board stack, memory backplane, and power transformer layout.

Electrical & Physical Specifications

Backplane Bus Communication Velocity & Scanning

The module governs backplane bus communication velocity across localized I/O chassis racks through dedicated bus timing logic. Logic solution sweeps run synchronously with input/output image table updates. This fixed scan priority maintains deterministic instruction timing and prevents signal latency during intensive block transfer operations across expansion backplanes.

Standard Delivery Hardware

• 1 x Allen-Bradley 1772-LP3 Processor Unit

• 1 x Power connection jumper plug

Field Installation & Mounting Rules

• Mounting Surface Preparation

  • Secure the chassis directly to a flat metal enclosure panel using heavy-duty bolts to support the 16.12 kg weight.

• Line Voltage Selection

  • Set internal terminal jumpers to match either 120 VAC or 240 VAC mains input before applying operating power.

• Enclosure Thermal Clearance

  • Maintain a minimum vertical clearance of 100 mm above and below the assembly for natural convection cooling.

• Earth Grounding Integrity

  • Connect a heavy gauge grounding strap directly from the chassis grounding stud to the main enclosure earth bus.

Technical System FAQs

• What is the required mains AC supply voltage for the 1772-LP3 unit?

  The processor operates on nominal 120 VAC or 240 VAC power supplies at 50/60 Hz frequency ranges.

• What current level does the processor draw under full operating load?

  The unit draws 2 A maximum when connected to 120 VAC, or 1 A maximum when wired for 240 VAC operation.

• Is hot-swapping allowed for this heavy processor assembly?

  No, main AC power must be isolated prior to physical installation, wiring adjustment, or unit removal.

• How does the unit maintain backplane bus communication velocity?

  Dedicated control buses regulate synchronous timing loops during execution of the internal instruction set.

• What thermal operating limits must be maintained in the enclosure?

  Ambient operating air temperatures surrounding the chassis must be maintained between 0 deg C and 60 deg C.

• How is the processor mounted inside an industrial panel?

  The unit utilizes a rigid chassis-mount structure secured via direct mounting holes to the backplate.

• Does the processor support external 1771 I/O chassis expansion?

  Yes, the unit routes control data to local or remote I/O chassis using dedicated parallel backplane cables.

• What grounding precautions are mandatory during field setup?

  The central chassis ground terminal must link directly to system ground to suppress high-frequency noise.