Product Details

Baumuller 3.7901A, also marked as 37901A, is a legacy rack plug-in memory expansion board and data storage PCB designed for Baumuller rack-based automation and servo control systems. This memory expansion board provides extra non-volatile and volatile memory space for the rack master controller, used to store motion programs, axis parameter sets, recipe data and historical fault logs. The data storage PCB integrates high-reliability memory chips, address decoding circuits and battery-backed retention logic to preserve critical configuration data during power loss. It supports fast data read and write access by the main CPU and allows users to save multiple machine recipes for quick product changeover. The multi-layer FR4 circuit board is conformal coated to protect memory chips and signal traces against dust, moisture and corrosive vapors inside industrial control cabinets. As an obsolete and hard-to-source discontinued spare, it serves as a direct drop-in replacement to restore extended program storage and recipe retention for ageing Baumuller control racks.

Basic Parameters

Brand: Baumuller

Model: 3.7901A, alternative marking: 37901A

Product Type: Battery-backed memory expansion PCB card

Main Function: Extended program storage, recipe data retention, fault log saving, parameter set backup, high-speed memory access

Interfaces: Rack backplane edge connector, low-power backup battery socket, access and fault LED indicators

PCB Treatment: Conformal coated multi-layer circuit board, UL 94V-0 flame retardant

Mounting: Plug-in installation for compatible legacy Baumuller control racks

Auxiliary Supply: 24 V DC logic supply with battery backup

Net Weight: Approximately 210 g

Condition: Original discontinued industrial spare

Supported Functions

This memory expansion board expands the storage capacity of the rack controller for complex automation projects. The data storage PCB receives read and write requests from the main control board, stores complete motion sequences, drive parameter groups and production recipes, and retains these datasets when the cabinet power is cut off. It supports fast recipe switching so operators can recall pre-saved machine settings without reconfiguring every axis manually. It works cooperatively with the master control board, fieldbus interface and I/O modules to run large automation programs that exceed the onboard memory limit of the base controller. If this memory extension card fails, stored recipes and extended programs will be lost, and the controller cannot load full machine operation sequences.

Core Functions

The core function of this memory expansion board is to expand the memory resources of the Baumuller rack controller and secure critical machine configuration data. The built-in backup circuit maintains memory content through power interruptions, avoiding costly reprogramming after power failure. It acts as a dedicated storage medium for custom machine logic and parameter archives. This data storage PCB is an indispensable spare to recover full program storage capability and retain original recipe management functions of legacy motion machinery.

Hardware Specifications & Environmental Features

Operating Temperature: 0°C ~ +60°C

Storage Temperature: -20°C ~ +75°C

Relative Humidity: 5%–95%, non-condensing

Housing: Bare coated PCB with backplane connector and battery holder

Protection: ESD protection for memory circuits, low-battery warning, data write protection, IP20

Anti-interference: Isolated memory power and filtering circuits to suppress electromagnetic noise inside cabinets

Compatibility: Suitable for legacy Baumuller modular control racks and matched servo drive units

Industry Applications: Applied in legacy petrochemical distributed control, old paper making production automation, material handling conveyor lines, packaging and textile machinery, water treatment remote signal collection and large conveyor remote I/O control racks.

Note: Confirm 800 series backplane compatibility, pulse signal type, counting mode and preset logic before ordering.

This is from our current stock.

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