On 29.04.2014 11:31, [email protected] wrote:
Thanks Dirk,
Does that mean I don't need to specify a terminator?
GPIB devices usually send a "end of message" marker (effectively a 9th
bit of the input bytes). The asyn GPIB support should set the eomReason
to ASYN_EOM_END when it gets it. drvVxi11.c does so.
So no, you don't need to specify a terminator. But if the device sends a
terminator in addition to the end marker, that terminator will end up in
the input as parsed by StreamDevice. But be aware that there may be GPIB
devices that do not send the end marker.
Dirk
Pete
-----Original Message-----
From: Dirk Zimoch [mailto:[email protected]]
Sent: 29 April 2014 08:35
To: [email protected]
Subject: Re: asyn vxi11 problem
Hi Peter,
Maybe you are using a too old version of StreamDevice?
For most devices, I try to read first 1 byte with ReplyTimeout and then the rest with ReadTimeout. For serial and socket this works fine. But GPIB devices must be addressed to talk and then deliver complete messages. If I now ask for only 1 byte, the GPIB driver reports overflow. (Unfortunately it does not store the message in some local input buffer where could pick it up later.)
Thus I have modified StreamDevice to handle GPIB devices differently and read larger messages. I have changed that behavior quite some time ago.
BTW: At the moment, I am working on a more flexible solution, because there are other devices, that behave similarly without having a asynGpibType interface (e.g. usbtmc). Progress is slow however because of lack of time.
Dirk
On 28.04.2014 16:11, [email protected] wrote:
I'm trying to communicate with a scope using a vxi11 protocol with
stream device & asyn.
I can connect to the device and send output commands which appear to
work, but whenever I try to read a reply I get:
2014/04/28 15:09:21.411 FE-SCOPE-ReadIdent: asynOverflow:
2014/04/28 15:09:21.412 FE-SCOPE-ReadIdent: I/O error from device
2014/04/28 15:09:21.412 FE-SCOPE-ReadIdent: Protocol aborted
Any suggestions for what may be happening?
Pete
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