The following brief overview of principal features illustrates the flexibility and performance that is available with the VMIVME-3122:

 • 16, 32 or 64 differential or single-ended analog inputs

 •16-bit A/D conversion

 • 381 Hz to 100 kHz selectable scanning rate for high-performance option, 381 Hz to 50 kHz for standard performance option

 • Programmable gains of x1 or x10Features of the VMIVME-3122 (Continued):

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

 • Programmable channel gains

 • 16- to 1,024-word dual port data buffer

 • Operation in short I/O (A16), standard (A24), or extended (A32) data space

 • Programmable channel block size and buffer size

 • Optional low pass input filters

 • Continuous and  burst operating modes

 • Free running operation or external/internal triggering

 • Bus interrupter for Midscan or Endscan indication

 • Programmable interval timer for timed data bursts

 • Direct cabling from VMIC signal conditioning boards

 • Initializes after a reset in autoscan mode with gain = x1

Functional Description

The VMIVME-3122  is a high-resolution, 16-bit, 64-channel Analog Scanning and Digitizing Input board for VMEbus system applications. 

Dual-ported data memory, on-board timers, automatically controlled gain and a programmable bus interrupter enable the VMIVME-3122 to support extensive analog 

input traffic, with minimum involvement of the host processor.

Analog inputs are scanned and digitized sequentially. The digital values are stored in a dual port data buffer which can be accessed at any time from the VMEbus. The gain of each channel can be programmed individually, or can be set in software for a fixed gain that is common to all channels. Channel gain is software selectable as x1 or x10. 

A/D converter voltage ranges are jumper-selectable for ±2.5 V, ±5 V, ±10 V, 0 to 5 V and 0 to 10 V.

When a system or program reset occurs, the board initializes in the 64-channel autoscanning mode at a rate of 100 KHz and all channel gains are initialized to unity 

(x1). After a reset operation, the program can select the timed burst or triggered burst 

modes, and can modify the block size, buffer size, and channel gains as necessary.