OVERVIEW

Official designation: Allen-Bradley 1775-MS4 (PLC-3, Error Correcting RAM Memory Module)

Role/Application: The 1775-MS4 is an Error Correcting RAM memory module providing 16K words of volatile program and data storage for use with the legacy PLC-3/10 processor.

KEY SPECS SUMMARY

Power: 2.5 A at 5 V DC, 150 mA at 15 V DC

Interfaces / Ports: PLC-3 chassis backplane

Indicators: Refer to the latest manufacturer manual.

Operating Temp: 0 to 60 degrees C

Platform / Compatibility: PLC-3/10 processor

Limit: 16K words RAM capacity

Lifecycle: Discontinued/Obsolete

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What are the backplane current requirements for the 1775-MS4 memory module during normal PLC-3 operation?

A: The module requires 2.5 A at 5 V DC and 150 mA at the positive and negative 15 V DC backplane supplies.

Wiring & Installation:

Q: What are the approximate dimensions of the 1775-MS4 module for physical replacement or repair considerations?

A: The dimensions are approximately 2.5 centimeters by 7.6 centimeters by 20.3 centimeters.

Troubleshooting & Compatibility:

Q: Which Allen-Bradley PLC processor models are compatible with the 1775-MS4 16K word memory module?

A: The 1775-MS4 module is primarily used with the Allen-Bradley 1775-L4 PLC-3/10 processor.

Replacement & Upgrades:

Q: Given that the 1775-MS4 is obsolete, what is the current long-term migration strategy for the PLC-3 system?

A: The standard long-term replacement and upgrade path for the obsolete PLC-3 system is to migrate to the ControlLogix platform.