Product Overview

The Allen-Bradley 1785-ME32​ is a 32K-word (32,768 words × 16 bits) Electrically Erasable Programmable Read-Only Memory (EEPROM) cartridge designed exclusively for use with Rockwell Automation’s PLC-5 family of programmable logic controllers, including both Classic (PLC-5/10, /12, /15, /25, /40, /60) and Enhanced (PLC-5/20E, /40E, /60E, /80E, /86E, /88E) processors that are equipped with a front-panel memory module socket. The Allen-Bradley 1785-ME32​ plugs directly into the designated EEPROM slot on the faceplate of a compatible 1785-Lx CPU, providing non-volatile storage for the controller’s application program, data tables, and selected configuration information independent of the processor’s battery-backed RAM. Because EEPROM technology requires no battery to retain data, the Allen-Bradley 1785-ME32​ serves as a critical disaster-recovery asset—allowing a complete program image to be saved to the cartridge and later loaded into a replacement processor during unplanned CPU failure, even months or years after the save operation, with zero data degradation.When used in a PLC-5 Enhanced processor, the Allen-Bradley 1785-ME32​ can be written to from the front keypad/display, via RSLogix 5 software using the “Save to EEPROM” or “Load from EEPROM” commands, or automatically configured for background save on certain firmware revisions. The 32K-word capacity accommodates small- to medium-complexity PLC-5 applications; for larger programs the 1785-ME64 (64K) or 1785-ME100 (100K, select models) cartridges are available, while the 1785-ME16 (16K) serves smaller applications. The Allen-Bradley 1785-ME32​ is hot-insertable/removable with the processor in Program or Remote Program mode (not recommended while in Run for write operations), and its solid-state construction with no moving parts makes it well suited to harsh industrial environments. As plants continue to maintain PLC-5-based assets pending full migration to ControlLogix, the Allen-Bradley 1785-ME32​ remains a frequently specified spare and lifecycle-support component for ensuring rapid system restoration and secure off-line program archiving.

Technical Specifications

Product Model | 1785-ME32 (also 1785-ME32/A, 1785-ME32/B)Manufacturer | Allen-Bradley / Rockwell AutomationProduct Type | PLC-5 Series EEPROM Memory Cartridge (Non-Volatile Program/Data Storage Module)Memory Capacity | 32 K Words (32,768 words × 16 bits; 1 word = 16 bits in PLC-5 architecture)Memory Technology | EEPROM (Electrically Erasable PROM), UV-erase NOT requiredCompatible Processors | 1785-L20E, 1785-L40E, 1785-L60E, 1785-L80E, 1785-L86E, 1785-L88E (Enhanced); 1785-L10, -L12, -L15, -L25, -L40, -L60 (Classic) with EEPROM socketInterface | Direct-edge connector to PLC-5 CPU front-panel memory module socketWrite Cycles (typical) | ≥ 10,000 erase/write cycles per IEEE Std 1000 for industrial EEPROMData Retention | ≥ 10 years at rated temperature (typical 20+ years per manufacturer characterization)Write Time (full cartridge) | Approximately 30–90 seconds depending on processor firmware and program sizeOperating Temperature | 0 °C to +60 °C (+32 °F to +140 °F)Storage Temperature | -40 °C to +85 °CHumidity (non-condensing) | 5 % – 95 % RHDimensions (L × W × D) | Approx. 85 mm × 55 mm × 10 mm (cartridge form factor)Weight | Approx. 40 g (0.09 lb)Mounting | Plugs into PLC-5 processor front-panel EEPROM socket (keyed)Certifications | UL Recognized Component, CE Marked, RoHS compliant (later revisions)Notes | Not battery-dependent; cannot be used as runtime RAM expansion—stores program/data image only

Main Features and Advantages

Non-volatile program retention without batteries: The defining advantage of the Allen-Bradley 1785-ME32​ is its independence from the PLC-5’s lithium backup battery. While the processor’s working memory (RAM) relies on a battery (1770-XYx) to retain the program during power loss, the Allen-Bradley 1785-ME32​ stores an image of the application in EEPROM cells that hold data for decades without any external power source. This eliminates “dead battery = lost program” scenarios when the cartridge has been kept current with the running logic via periodic saves.Rapid controller change-out and disaster recovery: In the event of a CPU failure, a technician can remove the Allen-Bradley 1785-ME32​ from the faulty processor, insert it into the replacement 1785-Lx CPU of the same or compatible type, select “Load from EEPROM” from the front keypad or RSLogix 5, and have the system running within minutes—no laptop, no cable, no uploaded file required. This dramatically reduces Mean Time To Repair (MTTR) in remote or unmanned facilities and is a common plant-standard practice for critical PLC-5 assets.Flexible save/load methods: The Allen-Bradley 1785-ME32​ can be programmed from RSLogix 5 via the online “Save to EEPROM” command (which writes the current processor memory image to the cartridge) or from the PLC-5’s built-in keypad/display on processors so equipped. Enhanced processors also support optionally configuring automatic EEPROM save on certain events via SFC or ladder logic using the EEPROM instructions, although this is less common due to EEPROM write-cycle limits. The cartridge can also be erased and re-used indefinitely within its write-cycle rating.Plant documentation and version control aid: Because the Allen-Bradley 1785-ME32​ holds an exact binary image of the controller’s memory—including program, data table initial values, and sometimes I/O configuration—it serves as a physical “golden copy” that can be labeled, dated, and stored in a controlled spare-parts cabinet alongside the as-built printed documentation. During audits or after unauthorized changes, comparing the running program to the EEPROM image (upload both and run a cross-reference) helps identify discrepancies.Legacy system compatibility across PLC-5 generations: The Allen-Bradley 1785-ME32​ works with both Classic and Enhanced PLC-5 processors that have an EEPROM socket, making it a universally stocked spare across mixed-vintage PLC-5 installations. However, note that program images saved from an Enhanced processor may not load correctly into a Classic processor (and vice-versa) due to architectural differences—the Allen-Bradley 1785-ME32​ itself is compatible, but the saved image must match the target CPU type.