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.