Product Overview

The Allen Bradley 1785-MJ provides dedicated, non-volatile program storage for classic Allen Bradley automation platforms. This 8K Word EEPROM Memory Cartridge acts as a permanent backup solution, safeguarding critical ladder logic and system configurations against unexpected power loss or battery failures. It integrates directly into standard PLC-5 and PLC-2/17 processor chassis to ensure immediate recovery during system reboots. We offer this component as a 100% Brand New and Original factory unit, allowing plant engineers to maintain legacy control systems without risking data corruption or code loss.

Technical Specifications

Engineering Advantages

• Permanent Data Retention: The 1785-MJ utilizes EEPROM technology to secure software files indefinitely. Unlike volatile RAM, this cartridge eliminates dependence on external lithium batteries, guaranteeing zero code loss during long-term seasonal plant shutdowns.

• Hardware-Enforced Write Protection: A mechanical, removable onboard jumper controls the write privileges of the cartridge. By physically pulling this jumper, field engineers prevent accidental overwriting, unauthorized modifications, or corrupted data transfers during routine operations.

• Direct Hardware Integration: The compact cartridge slides directly into the dedicated memory slot of compatible PLC-5 or PLC-2 processors. This internal installation method requires zero extra DIN rail space, zero external cabling, and draws power directly from the existing backplane.

• Rapid Fault Recovery: In the event of a main processor memory failure or battery depletion, the controller reads the backup image directly from the 1785-MJ cartridge. This automated restoration drastically minimizes Mean Time to Repair (MTTR) and avoids costly manual re-programming field service calls.

FAQs

• Can I insert or remove the 1785-MJ module while the PLC processor is powered?

  No. This module does not support Removal and Insertion Under Power (RIUP). You must completely shut off power to the chassis before installing or removing the 1785-MJ cartridge to prevent physical component damage or memory corruption.

• Which specific Allen Bradley processors accept this memory cartridge?

  The 1785-MJ supports classic-tier controllers, specifically the PLC-2/17 models (1772-LW and 1772-LWP) and early PLC-5 processors, including the PLC-5/10 (1785-LT), PLC-5/12 (1785-LT2), PLC-5/15 (1785-LT3), and PLC-5/25 (1785-LT4).

• How do I download my program to this EEPROM cartridge?

  You use standard 6200 or RSLogix 5 programming software to transfer your compiled ladder logic to the processor. From the software menu, execute the "Store to EEPROM" command while the write-protection jumper sits in the "Write-Enabled" position.

• What should I consider regarding the 8K word storage limit?

  This module features a fixed 8 Kiloword memory limit. It suits the legacy instruction sets of early PLC-5 systems perfectly. However, you must verify your project file size inside the programming software before purchasing to ensure it fits within the 8K limit.