VSDAC12/32
VMEbus 32 Channel ADC with Automatic Sampling

The VSAD12/32 is a 12-bit 32 channel A/D board with 10 microseconds conversion time. The VSAD12/32 can be accessed from VMEbus and optionally the local STEbus interface. The analogue front end consists of a 32 channel multiplexer, a software programmable instrumentation amplifier (gains of x 1, x 10, x 100 or x 1000), and a sample-and-hold amplifier. The input voltages can be either unipolar 0 to 5V or 0 to 10V, or bipolar -5V to 5V or -10V to 10V.

An EPLD-based control sequencer, gives the VSAD12/32 the ability to take samples automatically, at lower cost than boards with on-board processors. The control sequencer allows the board to be programmed to take a given number of samples (from 1 to 1024) and then, optionally, produce an interrupt to VMEbus or STEbus. The sampling rate can be varied under software control from 16 to 128 microseconds, in 8 microsecond steps. Sampling can be started under software control or by an external trigger input. The VSAD12/16 can also be programmed to switch between a chosen number of the multiplexed channels during sampling. A/D data is stored in RAM (4Kbytes) which is triple-ported to VMEbus and STEbus, making it ideal for capturing waveforms with precise conversion intervals, or capturing several waveforms for later comparison. Sections of memory not used by the A/D sampler can be used to send messages and status information between systems.

VMEbus Interface:

AD0, A16, D16, D08, (E0), D08(INT), RORA I (1-7)

STEbus Interface:

Slave interface in memory and I/O space with non-vectored interrupts.

Power consumption:

Typ 1.55A @ 5V

Features:

• 12-bit, 10 microsecond A/D, 32 differential channels
• Automatic sampling with data stored in on-board RAM
• Automatic channels switching
• Programmable gains, sample/hold
• Unipolar or bipolar
• Programmable number of samples and rate
• Expansion interface for D/A capability
• VMEbus interface
• STEbus interface (optional)

Ordering Information:

VSAD12/32    VMEbus 32 channel A/D with automatic sampling
VSAD12/32ST  VMEbus 32 channel A/D with automatic sampling, with STEbus interface