OVERVIEW

Official designation: Allen-Bradley 1775-AC (PLC-3, Chassis Unit)

Role/Application: This component is a heavy-duty, six-slot expansion chassis that provides a housing and backplane for PLC-3 processor and I/O modules, enabling system expansion and reliable module organization.

KEY SPECS SUMMARY

Power: 5A from 5V DC, 80mA from 15V DC via backplane

Interfaces / Ports: Backplane connectors, 25-pin parallel output

Indicators: LED status indicators, Refer to the latest manufacturer manual.

Operating Temp: 0 to 60 degrees C

Platform / Compatibility: PLC-3 processor system, 1771-I/O chassis

Limit: Six module slots, 40 pounds (18 kilograms) max weight

Lifecycle: Discontinued/Obsolete

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What are the dimensions of the 1775-AC chassis for mounting and space planning?

A: The chassis dimensions are 19 inches wide by 20 inches high by 14.5 inches deep.

Wiring & Installation:

Q: How is chassis communication established in a multi-chassis PLC-3 system?

A: Chassis expansion requires an expansion module and cable set, connecting through 50-pin connectors.

Troubleshooting & Compatibility:

Q: How is the chassis ID configured for communication in a multi-chassis PLC-3 system?

A: The chassis identification number is set using three switches located on the backplane of the unit.

Replacement & Upgrades:

Q: What is the recommended migration path for the discontinued PLC-3 and its 1775-AC chassis?

A: Refer to the latest manufacturer manual for the recommended migration path to a modern PLC platform.