Experimental Physics and
Industrial Control System

John Faucett wrote:

> I am writing device support for a message-based VXI module that
> supports two modes of data transfer:
>
> (1) Via a message, specifically through the SCPI "TRACE #" command.
> This is too slow -- 1000 words takes 30 seconds.
>
> (2) Via shared memory, using the SCPI "SMEM" command.  The
> documentation shows an example using the VISA viMoveAsync routine,
> but I believe there is no VISA library for EPICS.
>
> Can anyone give me pointers on writing a routine using shared memory
> transfer?  The VXI slot-0 controller is a hkbaja60 module.

Does your VXI module support Fast Data Channel (FDC protocol) ?
It uses local memory or remote memory to transfer data, which is
very fast.  I used FDC protocol for a tektronix VXI based scope
to trasfer the waveform, and achieved 16-30KB/s at single cycles.

Cheers,
S. Kate Feng
Brookhaven National Lab.
National Synchrotron Light Source
Bldg. 725D
Upton, New York  11973-5000

Email: [email protected]

References:

VXI shared memory transfer John Faucett

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