GE VMIVME-3122 High Performance 16-bit Analog-to-Digital Converter Boards

Product Description

The VMIVME-3122 is a member of VMIC's extensive VMEbus analog I/O product line.

It features 16-bit digital resolution, program-controlled gain, selectable slew rates, and auto-scanning for 64 differential or single-ended channels,

Auto-scan for 64 differential or single-ended analog inputs.

The VMIVME-3122 has excellent dynamic range and analog input channel density. Multiple modes of operation are supported, including auto-scan, data burst, and external synchronization.

The board interfaces directly with VMIC's family of signal conditioning boards to digitize the outputs of thermocouples, RTDs, and strain gages.

Individual channel gains can be downloaded for use during scanning operations, or the board can be configured for fixed gains. The boards can be configured for fixed gain common to all channels.

Multiple boards can be synchronized together, allowing up to 16 boards to start each scan simultaneously.

Interval timers, bus interrupters, channel counters, and mid-scan/end-of-scan flags simplify monitoring of data in the dual-port data buffer.

System applications that can benefit from the features of the VMIVME-3122 include factory automation, process control, data acquisition systems, training simulators, and laboratory instrumentation.

The following overview of key features illustrates the flexibility and performance of the VMIVME-3122:

- 16. 32. or 64 differential or single-ended analog inputs

- 16-bit A/D conversion

- Selectable sweep rates from 381 Hz to 100 kHz (high performance option), 381 Hz to 50 kHz (standard performance option)

- Programmable gain of x1 or x10

- A/D converter ranges of ±2.5 V, ±5 V, ±10 V, 0 to +5 V, 0 to +10 V

- Programmable channel gain

- 16- to 1.024-word dual-port data buffer

- Operates in short I/O (A16), standard (A24), or extended (A32) data spaces

- Programmable channel block size and buffer size

- Optional low-pass input filter

- Continuous and burst operation modes

- Free-run or external/internal trigger

- Bus interrupter for mid-scan or end-scan indication

- Programmable interval timer for timing data bursts

- Direct wiring from VMIC signal conditioning boards

- Initialized after reset in Auto Scan mode, gain = x1

Functional Description

The VMIVME-3122 is a high-resolution, 16-bit, 64-channel analog scan and digitizing input board for VMEbus system applications.

Dual-port data memory, on-board timers, automatic gain control, and programmable bus interrupters enable the VMIVME-3122 to support large amounts of analog input traffic with minimal host processor involvement.

Analog inputs are scanned and digitized sequentially. Digital values are stored in dual-port data buffers that are readily accessible from the VME bus.

The gain of each channel can be programmed individually or set by software to a fixed gain common to all channels. Channel gains are software selectable to x1 or x10.

The A/D converter voltage ranges are jumper-selectable to ±2.5 V, ±5 V, ±10 V, 0 to 5 V, and 0 to 10 V. The A/D converter voltage ranges can be set to ±1 or x10 by software.

Upon system or program reset, the board will initialize in 64-channel auto-scan mode at 100 KHz with all channel gains initialized to 1 (x1).

After the reset operation, the program can select timed burst or triggered burst mode and modify the block size, buffer size, and channel gains as desired.

The channel block can be adjusted to 1. 8. 16. 32. or 64 channels, and the data buffer size can be selected from 16 to 1.000 channels.

The data buffer size is selectable from 16 to 1.024 data words in binary increments.

In standard performance mode, the board must be reprogrammed after a reset to obtain a 50 kHz scan rate. The value of $00F7 must be written to relative address $0006.

Timed Data Bursts are controlled by an interval timer that provides repeat or single burst intervals of up to 687 seconds.

A burst can contain from 8 to 1.024 channel samples. A data ready flag can be used in the middle or at the end of a scan, and an interrupt request can be generated at the same time as the flag.

An interrupt can also be initiated after a specific number of samples have been acquired.