[time-nuts] Timelab, two SR620s and losing samples
phk at phk.freebsd.dk
Mon Jan 18 07:59:41 UTC 2016
In message <569BCEBE.20307 at erols.com>, Chuck Harris writes:
>Talk-only mode is by intention, an exclusive mode, where
>there is one talker, and one listener on the bus.
There can *always* be multiple listeners on GPIB, this is
why it has a three wire handshake.
The slowest listener sets the pace, individually for each byte.
>GPIB is half duplex.
>You have to turn the line around to tell it
There is no requirement to turn the line around (= send commands)
between measurements. EOI is only indicative, it does not require
an UNTALK+TALK sequence.
Most instruments can be commanded to measure and spew data at you
in "talk-only" fashion.
> Talk-only avoids that.
Talk-only is one way to avoid that.
As I said from the start: Talk-Only doesn't really make that much
difference, the three-wire handshake is sufficient to cause trouble.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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