XYCOM XVME-490/1 Product Description

I. Product Overview

XVME-490/1 is a 6U dual-high VMEbus four-channel RS-232C serial communication module launched by XYCOM (now under Pro-face). It belongs to the XVME-490 standard model series and is specifically designed for high-density serial communication in VME architecture. Its core positioning is as an industrial-grade RS-232C communication card with P2 interface output on the backplane, providing 4 independent programmable asynchronous serial ports. It is suitable for industrial automation, process control, test measurement, and the expansion of old VME systems with serial ports. This module has been officially discontinued and is mainly available in second-hand, refurbished, and inventory spare parts in the market. 

Core Positioning

As a VMEbus standard peripheral device, XVME-490/1 focuses on "6U dual high + 4 RS-232C + P2 backplane output + independent baud rate generator + multi-protocol support + industrial-grade reliability". Each slot integrates 4 standard serial ports, using backplane P2 interface wiring to free up the front panel space, suitable for centralized wiring in the chassis and multi-module stacking scenarios, addressing the pain points of messy wiring and low slot utilization in traditional front-out serial port cards.

II. Core Functional Characteristics

1. Standard VMEbus interface (fully compatible with slave devices)

Completely adheres to the IEEE 1014 VMEbus specification, compatible with all 6U VME chassis and backplanes, operates in standard slave device mode, supports A16 short address space, base address configured via jumpers, fixed at 1KB address boundary to avoid system address conflicts. Data width compatible with D08, compatible with 8-bit VME master controller, backplane connection uses P1 (bus signal) / P2 (serial signal) connectors, supports VME standard interrupts (I1-I7) and system fault signals (SYSFAIL), plug-and-play.

2. 4 independent RS-232C asynchronous serial channels (core function)

Equipped with 2 Zilog Z8530 serial communication controllers (SCC), providing 4 completely independent, software-programmable RS-232C interfaces (channels 0-3), each equipped with an independent baud rate generator, channels do not interfere with each other, can simultaneously connect terminals, printers, PLCs, instruments, Modems and other standard RS-232C devices.

Baud rate range: supports 50 bps - 115.2 kbps programmable, default 9600 bps, each channel independently set, suitable for low-speed to medium-speed data transmission scenarios.

Data format: programmable configuration of data bits (5/6/7/8), stop bits (1/1.5/2), parity bits (none / odd / even), default 8N1, compatible with all standard asynchronous communication protocols.

Electrical characteristics and transmission distance: standard RS-232C level (±12V), maximum transmission distance 15 meters, suitable for short-distance device interconnection.

Modem control: each channel provides complete Modem control signals (DTR, DSR, RTS, CTS, RI, DCD), supports hardware flow control and standard Modem connection, ensuring stable data transmission.

Multi-protocol support: in addition to asynchronous communication, also supports byte synchronous, HDLC/SDLC bit synchronous protocols, suitable for dedicated data link communication scenarios.

3. Backplane P2 interface output design (unique advantage)

Different from XVME-400 (front panel output), the 4 serial port signals of XVME-490/1 are all output through VME backplane P2 connectors, the front panel has no serial port interface, frees up the front panel space, facilitating centralized wiring in the chassis, cable organization, suitable for multi-module dense stacking and neat wiring requirements of industrial control cabinets, reducing interference and maintenance difficulty caused by messy front panel cables.

4. Flexible interrupts and data reception/transmission control

Supports multiple event interrupts, including data reception / transmission completion, reception errors (odd/even / frame / overflow), Modem signal status changes, etc., can shield any channel interrupt, interrupt vectors can be configured (a total of 16 independent vectors), suitable for high real-time data transmission scenarios. Each channel has an independent receive and transmit buffer, supports query or interrupt-based receive and transmit, meeting different system architecture requirements. 5. Industrial-grade high-reliability design

Standard operating temperature range: 0℃ to +65℃, suitable for harsh environments such as industrial sites and test equipment; the circuit board adopts multi-layer board wiring and gold-plated finger design, with enhanced noise suppression for critical circuits, strong anti-static and anti-interference capabilities, and stable long-term operation. The front baffle is equipped with power and operation indicator lights, facilitating quick troubleshooting of module status in the field.

III. Hardware Specifications Details

Bus interface specifications

Bus protocol: IEEE 1014 VMEbus, standard slave device mode;

Address space: A16 short address, jumper configuration 1KB boundary base address;

Data width: D08;

Interrupt support: VME standard interrupt I1-I7, 16 configurable interrupt vectors;

Backplane interface: P1 (bus), P2 (serial signal);

Size: 6U (233.4mm×160mm), single slot;

Weight: Approximately 0.7kg.

Serial channel specifications

Channel quantity: 4 independent RS-232C interfaces;

Communication controller: 2 Zilog Z8530 SCC;

Baud rate: Programmable from 50 bps to 115.2 kbps per channel, independent;

Data format: 5/6/7/8 data bits, 1/1.5/2 stop bits, no / odd / even parity;

Electrical standard: RS-232C (±12V);

Transmission distance: Up to 15 meters;

Protocol support: Asynchronous, byte synchronous, HDLC/SDLC;

Control signals: Each channel with complete Modem hardware flow control signals.

Electrical and environmental specifications

Power supply: +5V DC (VME bus power supply), typical power consumption approximately 1.1A;

Operating temperature: 0℃ to +65℃;

Storage temperature: -40℃ to +85℃;

Humidity: 5%–95% RH (non-condensing);

Anti-vibration: Compliant with industrial standards, suitable for equipment vibration environments.

IV. Typical Application Scenarios

1. Centralized connection of multiple serial ports in industrial automation

Suitable for factory workshops and assembly line control scenarios, through backplane P2 interface wiring, connect 4 RS-232C devices (such as operation terminals, printers, barcode scanners, PLC), a single module realizes unified connection of multiple devices, the front baffle has no messy cables, simplifies the system architecture, and enhances the neatness of the control cabinet.

2. Interconnection of test measurement instruments

Used for industrial test equipment and data acquisition systems, connect oscilloscopes, signal generators, data recorders, etc. with RS-232C interface, 4 independent channels can simultaneously collect data from multiple instruments, medium-high baud rates meet the requirements for test data transmission, suitable for laboratories and industrial test sites.

3. Serial port expansion of outdated VME systems

Directly replace single-channel or dual-channel serial port modules in outdated systems, no need to modify the chassis structure, utilize the P2 backplane output characteristic to adapt to the original wiring, expand to 4 RS-232C serial ports, suitable for maintenance of outdated VME equipment in military, aerospace, and industrial control fields, extending equipment lifespan.

4. Process control and monitoring systems

Used for process control scenarios in energy, chemical, water treatment, etc., connect field instruments, sensors, operation terminals, etc., through RS-232C interface to achieve data collection and command issuance, industrial-grade wide temperature design adapts to harsh field environments, ensuring stable communication.

V. Installation and Programming Key Points Installation steps

Preparations: Ensure that the P1/P2 slots of the VME chassis are intact and the +5V power supply is stable; according to the pin definitions of the P2 interface, make the corresponding serial cable (RS-232C shielded cable).

Jumper configuration: Set the A16 base address jumper to avoid address conflicts; configure the interrupt priority and vector jumper (if interrupts are needed); confirm that the serial port mode is RS-232C (hardware fixed, no additional configuration required).

Module insertion: Align the XVME-490/1 with the 6U slot and push it in smoothly to ensure that the gold fingers make good contact with the backplane P1/P2, and tighten the panel fixing screws.

Cable connection: According to the pin definitions of P2, connect the 4 serial ports' TX, RX, GND, and Modem control signals to the device, single-ended ground the shield layer, and keep it away from strong interference devices.

Power-on self-test: After the chassis is powered on, the POWER indicator light is constantly on, indicating that the module is running normally; when the channels transmit and receive data, the corresponding status indicator lights flash.

Programming process (simplified)

Address mapping: Configure the A16 base address, map the Z8530 SCC register to the system memory, and establish the communication channel between the CPU and the module.

Channel initialization: Write the configuration word to the SCC control register, set the baud rate, data format, flow control method, and communication protocol for each channel.

Data transmission: Send/receive data through the SCC data register, support query mode (reading status register) or interrupt mode transmission, handle the completion of data transmission and error interrupts.

Interrupt configuration: Enable the required interrupts, write the interrupt service program to handle real-time data and fault alarms, and improve the system response speed.

Reset operation: When the system resets, the module clears the transmission and reception buffers, turns off the interrupts, and clears the flags to ensure communication security.

Six. Core advantages

1. 6U dual high + 4 channels RS-232C, high-density integration

Each 6U slot integrates 4 standard RS-232C serial ports, the channel quantity is moderate and the density is high, suitable for multi-device centralized access scenarios, compared with single/double-channel modules, it saves slots and hardware costs.

2. P2 backplane output, neat wiring and easy maintenance

All serial signals are output through the P2 backplane, the front cover has no cables, facilitating centralized wiring and line arrangement inside the chassis, reducing the electromagnetic interference and maintenance difficulty caused by messy cables, suitable for the neatness requirements of industrial control cabinets.

3. Independent baud rate + multiple protocols, strong adaptability

Each channel is equipped with an independent baud rate generator, with a programmable range of 50 bps - 115.2 kbps, supporting asynchronous, synchronous, HDLC/SDLC multiple protocols, suitable for different serial port devices and communication scenarios, with high flexibility.

4. Industrial-grade wide temperature + stable design, high reliability

0℃ - +65℃ wide temperature design, multi-layer board wiring + gold-plated gold fingers, anti-interference, anti-vibration, suitable for industrial harsh environments; the Z8530 controller is mature and stable, with a low failure rate during long-term operation.

5. Standard VME bus, easy integration and upgrade

Fully compatible with the VMEbus specification, directly compatible with existing 6U VME systems; simple configuration, convenient wiring, can directly replace old serial port modules, supports upgrading of old systems and building of new systems, with strong compatibility.

Seven. Precautions

The module has been discontinued, when purchasing, prefer to choose second-hand/reconditioned spare parts with complete test reports, check the model (XVME-490/1) and version, to avoid faulty or incompatible modules.

Serial port is standard RS-232C level,严禁 connecting RS-422/RS-485 differential signals， otherwise burn the interface circuit； The transmission distance should be strictly controlled within 15 meters. For long-distance scenarios, it is recommended to use RS-485 modules (such as XVME-491).

The power supply is +5V bus power supply, ensuring voltage stability (±5%), to avoid communication abnormalities caused by voltage fluctuations; do not reverse the power supply connection to prevent module damage.

The wiring at the site should separate the strong and weak electrical lines, with the shielding layer grounded at one end, and kept away from strong interference equipment such as frequency converters and motors to reduce the impact of electromagnetic interference on the signals and avoid data transmission errors.

The operating temperature is 0℃ to +65℃. During installation, ensure that the chassis has good ventilation to avoid overheating; in high-frequency communication scenarios, appropriately reduce the baud rate to extend the module lifespan.

During installation and maintenance, take precautions against static electricity, wear anti-static wrist straps, and operate on an anti-static workbench; before plugging or unplugging the module, cut off the power supply of the chassis to prevent damage to the backplane and the module due to live insertion or unplugging.