OVERVIEW

Official designation: Allen-Bradley 1775-MED (PLC-3, Error-Correcting RAM Memory Module)

Role/Application: This single-slot module provides 128K words of volatile RAM program and data storage for the PLC-3 controller, featuring Error Correction Code (ECC) for high data integrity.

KEY SPECS SUMMARY

Power: 5 V DC and 15 V DC from chassis backplane

Interfaces / Ports: Backplane connector

Indicators: Refer to the latest manufacturer manual.

Operating Temp: 0 to 60 degrees C

Platform / Compatibility: PLC-3 processor system, single slot chassis mount

Limit: Capacity is 128K 16-bit words

Lifecycle: Discontinued/Obsolete

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the exact storage capacity of the 1775-MED module and its primary feature?

A: The module provides 128K words of RAM storage and incorporates Error Correction Code technology for reliability.

Wiring & Installation:

Q: Does the 1775-MED module require external battery backup for data retention?

A: As a volatile RAM module, it requires a battery in the processor or chassis to retain data during power loss.

Troubleshooting & Compatibility:

Q: What type of error is the error-correcting feature of the 1775-MED designed to prevent?

A: The ECC feature is designed to detect and correct single-bit memory errors, enhancing system reliability.

Replacement & Upgrades:

Q: What is the current recommended Allen-Bradley platform for migrating obsolete PLC-3 systems?

A: The recommended migration path is the ControlLogix platform, which offers modern hardware and software tools for conversion.