XYCOM XVME-100 (VMEbus 3U Memory Expansion Module) Detailed Product Description
 I. Product Overview

XYCOM XVME-100 (Material Number 74100-001) is a 3U single-height VMEbus standard memory expansion module launched by XYCOM (now part of Acromag). It is specifically designed to provide flexible RAM/ROM/EEPROM storage expansion for VME bus industrial control systems, supporting data power-off protection and independent configuration. It is suitable for long-life industrial equipment, embedded systems, and outdated VME platforms. The product has been discontinued and the market is mainly composed of second-hand / refurbished spare parts. It has strong compatibility, reliable data, and stable long-term operation. 

II. Model Positioning and Core Functions

Model Positioning: XVME-100 is a standard 3U memory module. There are no derivative sub-models in the same series. It is compatible with all standard 3U VME enclosures and backplanes, and is the core expansion unit for program storage, data caching, and parameter backup in VME systems.

Core Functions:

System Program Storage: Carries the firmware of VME master control modules (such as XVME-661), operating systems, and applications. Supports EPROM/ROM solidification and RAM dynamic operation;

Critical Data Backup: Through battery backup of RAM or EEPROM, stores process parameters, equipment status, and calibration data, and does not lose data in case of power failure;

Expansion for Old Systems: Adds storage capacity to existing VME platforms without replacing the master control and backplane, extending the lifespan of equipment;

Embedded System Development: Used for embedded program debugging, data caching, and log storage in fields such as military, aerospace, and rail transportation.

III. Core Functional Characteristics

1. Standard 3U VMEbus Interface, Seamless Compatibility with System

Fully complies with VMEbus C.1 standard, 3U single-slot design, supports A24 address space and DTB slave device mode, compatible with all standard 3U VME enclosures and backplanes, compatible with all XYCOM VME modules and third-party standard VME devices, plug-and-play, no complex configuration required.

2. Flexible Configuration of Dual Storage Groups, Support for Multiple Types of Chips

Board-mounted 2 independent storage groups (Bank1/Bank2), each group has 4 28/32-pin JEDEC standard slots, a total of 8 slots, supports RAM, EPROM, mask ROM, and EEPROM chips, each group can independently configure chip type, capacity, and speed, suitable for different storage requirements:

Maximum Capacity: RAM/EPROM/mask ROM 1MB; EEPROM 256KB;

Supported Chip Specifications: 8K×8, 16K×8, 32K×8, 64K×8, 128K×8 (EEPROM limited to 32K×8 and below);

Speed Compatibility: 100ns, 150ns, 200ns, 250ns, suitable for different bus timing requirements.

3. Battery Backup for Data Protection, Multiple Security Mechanisms

Board-mounted battery backup: Integrated 1.4Ah lithium battery, typical lifespan 6 years, specifically powered for CMOS RAM, automatically switches when power failure occurs, preventing data loss;

Dual Backup Power Options: Supports board-mounted battery or VME backplane + 5V STDBY backup power, switchable through jumpers, suitable for different power supply scenarios;

Undervoltage Protection Circuit: Built-in power monitor, +5V below 4.75V automatically disables storage chips to prevent data write errors due to low voltage;

Data Write Protection Design: Automatically locks write operations when power is abnormal to avoid data damage, ensuring the security of critical parameters.

4. Independent Jumpers for Configuration, Compatible with Multiple System Addresses

Board-mounted multiple sets of configuration jumpers, can be independently set:

Storage Group Base Address (A24 space mapping);

Chip Speed Matching (100ns-250ns);

Backup Power Mode (Battery/STD BY);

Write Protection and Reset Signal Linkage;

No need to modify hardware, through jumpers can adapt to different system address planning, avoiding address conflicts.

5. Industrial-grade High Reliability Design, Adaptable to Harsh Environments

Wide Temperature Operation: Working temperature 0℃～+65℃, storage temperature **-40℃～+85℃** covers industrial site temperature fluctuations; Anti-vibration / Shock Resistance: 3U reinforced board card, metal panel fixation, anti-vibration 1g (10-100Hz), anti-shock 15g, suitable for equipment vibration and transportation shock;

Electromagnetic Compatibility: Compliant with CE/FCC Class A standards, board card gold-plated gold fingers, shielding design, anti-static, anti-electromagnetic interference, can operate stably near strong interference equipment such as frequency converters and motors;

Low Power Consumption Design: Typical power consumption 4.5W (+5V@900mA), maximum 5W, no additional cooling required, low heat generation and high stability during long-term operation;

6. Status Visual Indication, Fault Quick Location

The panel is equipped with **POWER (power), BATT (battery), FAIL (fault)** three sets of LED indicators:

POWER: Always on indicates +5V power supply is normal;

BATT: Lights up indicates battery backup activation, flashes indicate low battery;

FAIL: Always on indicates power anomaly, battery failure or storage error;

No software required to quickly determine module status, maintenance is efficient and convenient.

Four. Hardware Specification Overview

Bus and Interface

Bus standard: VMEbus C.1 (compatible with 2.0/3.0);

Address space: A24 (16MB addressing range);

Device mode: DTB slave device;

Slot Specifications: 8 28/32-pin JEDEC slots, divided into 2 groups (Bank1/Bank2).

Storage Configuration

Supported chips: RAM (CMOS), EPROM, mask ROM, EEPROM;

Maximum capacity: RAM/EPROM/ROM 1MB; EEPROM 256KB;

Chip speed: 100ns, 150ns, 200ns, 250ns (jumper selection);

Backup power: 1.4Ah lithium battery (typical life 6 years) or +5V STDBY.

Electrical Parameters

Operating power supply: +5V DC ±5%, typical 900mA, maximum 1A;

Power consumption: typical 4.5W, maximum 5W;

Power supply protection: overvoltage, overcurrent, reverse connection protection, under-voltage lockout (4.75V threshold).

Environmental and Mechanical Parameters

Operating temperature: 0℃～+65℃;

Storage temperature: -40℃～+85℃;

Humidity: 10%～90% RH (no condensation);

Anti-vibration: 1g (10–100Hz);

Anti-shock: 15g;

Size: Standard 3U VME (100mm×160mm), single slot;

Weight: Approximately 0.3kg.

Five. Main Application Scenarios

1. VME Master Control System Program Storage

Combined with XVME-661, XVME-103 and other VME master control modules, it stores operating systems, firmware and applications, supports EPROM fixed programs, RAM dynamic operation, suitable for semiconductor equipment, industrial robots, metallurgical control and other scenarios.

2. Critical Process Parameter Backup

In fields such as chemical industry, power, water treatment, etc., it stores calibration data, process formulas, operation logs, through battery backup RAM or EEPROM to achieve power-off preservation, avoiding parameter loss after power-off, ensuring production continuity.

3. Military and Aerospace Embedded Systems

Used for onboard control, radar data processing, navigation systems, etc. in high-reliability, long-life cycle scenarios, providing program固化， data caching and power-off protection， meeting military standards and harsh environment requirements.

4. Upgrade and Replacement of Old VME Systems Replace the old 3U memory module of XYCOM (such as XVME-101) directly. No need to redesign the hardware or rewrite the program. It is compatible with the existing VME bus architecture and the main control module, reducing the renovation cost and downtime.

5. Embedded System Development and Debugging

As the program storage and data cache unit of the VME bus embedded development platform, it supports program burning, online debugging and data log recording, suitable for university research, enterprise R&D and other scenarios.

Six. Installation and Maintenance Key Points Installation steps

Box Preparation: Select a standard 3U VME chassis with a backplane, and confirm that the +5V power supply is normal and the slots are not oxidized;

Wire Configuration: According to the system address planning, set the base address of the storage group, chip speed, and backup power mode (battery / STD BY);

Chip Installation: Insert the RAM/EPROM/EEPROM chips in the direction indicated by the slot markings, ensuring good contact of the pins, no skewing, or loose insertion;

Board Installation: Align the 3U slot and push it in smoothly, tighten the panel fixing screws to ensure good contact between the gold fingers and the backplane;

Power On Debugging: After powering on, the POWER light is always on; the BATT light is on indicating normal backup; the FAIL light is off indicating normal module operation; through the read/write test of the master control module, verify the storage function and data backup effectiveness.

Daily Maintenance

Regular Cleaning: Disconnect the power supply every 3 months, wipe the board and gold fingers with a dry soft cloth, the gold fingers can be lightly wiped with an alcohol cotton swab to prevent oxidation and poor contact;

Battery Check: Check the BATT indicator light status every 1 year, replace the lithium battery in time when it flashes; check the contact of the battery holder;

Configuration Check: Regularly check if the wire configuration is loose or offset, ensuring the correct address, speed, and backup mode configuration;

Chip Check: Check if the chip is loose, burned out, or the pins are oxidized, and replace the damaged chip in time;

Environmental Monitoring: Keep the working environment temperature and humidity within the allowable range, avoid dust, corrosive gases, and strong electromagnetic interference.

Common Fault Troubleshooting

POWER light does not light up: Check if the +5V power supply on the VME backplane is normal; troubleshoot oxidation or poor contact of the gold fingers; check if the power circuit of the board is damaged;

BATT light flashes: Battery power is insufficient, replace the 1.4Ah lithium battery; check if the contact of the battery holder is good;

FAIL light is always on: Check if the +5V voltage is lower than 4.75V; troubleshoot battery failure; check if the chip is inserted in the wrong direction, damaged or short-circuited;

Data Loss: Check if the battery is ineffective; confirm the correct configuration of the backup power wire; troubleshoot chip damage or abnormal write protection;

Read/Write Errors: Verify if the chip speed wire is matched; check if the address configuration is conflicting; troubleshoot loose soldering or poor contact of the chip pins.

VII. Product Core Advantages

XYCOM XVME-100 is a 3U VME bus-specific high-reliability memory expansion module. Its core advantages lie in standard VME compatibility, flexible dual storage group configuration, support for multiple chip types, power-off data protection, industrial-grade high reliability, compact and easy installation and maintenance. It provides stable program storage and data backup capabilities for VME systems, suitable for harsh working conditions and long lifecycle requirements, with stable spare parts, sufficient second-hand market, and high cost performance. It is a reliable choice for building and maintaining VME industrial control systems.