[time-nuts] Timelab, two SR620s and losing samples

Chuck Harris cfharris at erols.com
Sun Jan 17 12:26:22 EST 2016


Talk-only mode is by intention, an exclusive mode, where
there is one talker, and one listener on the bus.  There
can be exceptions where there are more than one listener,
but that tends to be unusual.

Addressed mode can have one or more instrument on the
bus.  Although addressed mode is fully orchestrated by
the controller, the controller can easily interleave
things in a way that can cause unintended latency in a
critical instrument.

-Chuck Harris

Magnus Danielson wrote:
> Poul-Henning,
>
> On 01/17/2016 12:52 PM, Poul-Henning Kamp wrote:
>> --------
>> In message <569B61CF.3030708 at rubidium.dyndns.org>, Magnus Danielson writes:
>>
>>>> This is a common misunderstanding:  Talk-only does *not* protecting you
>>>> against timing issues on GPIB.
>>>>
>>>> On RS-232, yes, but not on GPIB.
>>>
>>> Agree, to some degree. It's not a guarantee.
>>>
>>> I think you should develop that line of thought, to detail why it helps
>>> on GPIB and why not on serial.
>>
>> It's really very simple:  RS-232 sends blind, you don't even need to
>> know if there is a receiver or what it does.  If the receiver cannot
>> keep op, data is simply lost.
>>
>> GPIB handshakes every byte, so the actions of the receiving end affects
>> the transmitting end - in particular if the receiver cannot keep up.
>>



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