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Groups > comp.lang.python > #34425

Re: problem with usbtmc-communication

Date 2012-12-06 15:10 -0500
From Dave Angel <d@davea.name>
Subject Re: problem with usbtmc-communication
References (4 earlier) <fc36067e-9b74-4eed-b1db-92ee5760af30@c16g2000yqi.googlegroups.com> <mailman.533.1354746072.29569.python-list@python.org> <d8253611-dab9-461a-8b82-9c52287718a9@w8g2000yqm.googlegroups.com> <mailman.564.1354805416.29569.python-list@python.org> <123edfab-b46a-4a47-8b73-3f47e807e074@c16g2000yqi.googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.585.1354824648.29569.python-list@python.org> (permalink)

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On 12/06/2012 02:41 PM, Jean Dubois wrote:
> On 6 dec, 15:50, w...@mac.com wrote:
>> <snip>
>> Sorry about the misunderstanding (and subsequent waste of bandwidth).  However, if you will look at the serial reads and writes in that handler, you will see that it does things like "serial.read(n)" where "n" is an explicit number, the number of bytes to be read from the serial buffer.
>>
>> -Bill
> I tried changing measurementcurr=usbkeith.readline() to
> measurementcurr=usbkeith.read(10000)
> but this leads to trouble with the usbtmc-thing:
>
> Measured current 1:
> Traceback (most recent call last):
>   File "./keith2200rev2.py", line 26, in <module>
>     measurementvolt=usbkeith.read(10000)
> IOError: [Errno 110] Connection timed out
>
> and hereafter I need to restart the Keithley...:-(
I can't see why you used a count of 10000.  Isn't the whole problem
supposed to be because it doesn't produce a whole line at a time?  So
after requesting a measurement, if you know the size, use that in the
read() method.  And if you don't know the size, read it one byte at a
time till it make sense.

-- 

DaveA

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Thread

[newbie] problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-04 04:14 -0800
  Re: [newbie] problem with usbtmc-communication wrw@mac.com - 2012-12-04 09:33 -0500
    Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-04 08:12 -0800
      Re: problem with usbtmc-communication wrw@mac.com - 2012-12-05 10:26 -0500
        Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-05 12:38 -0800
          Re: problem with usbtmc-communication wrw@mac.com - 2012-12-05 17:21 -0500
            Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-06 05:50 -0800
              Re: problem with usbtmc-communication wrw@mac.com - 2012-12-06 09:50 -0500
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-06 11:41 -0800
                Re: problem with usbtmc-communication Dave Angel <d@davea.name> - 2012-12-06 15:10 -0500
                Re: problem with usbtmc-communication wrw@mac.com - 2012-12-06 15:15 -0500
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-07 05:46 -0800
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-10 05:31 -0800
                Re: problem with usbtmc-communication wrw@mac.com - 2012-12-10 10:34 -0500
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-10 22:58 -0800
                Re: problem with usbtmc-communication wrw@mac.com - 2012-12-11 09:34 -0500
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-11 12:48 -0800
                Re: problem with usbtmc-communication wrw@mac.com - 2012-12-11 21:21 -0500
                Re: problem with usbtmc-communication Jerry Hill <malaclypse2@gmail.com> - 2012-12-11 19:49 -0500
                Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-12 08:16 -0800
          Re: problem with usbtmc-communication Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-12-05 18:08 -0500
  Re: [newbie] problem with usbtmc-communication Terry Reedy <tjreedy@udel.edu> - 2012-12-04 14:55 -0500
    Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-06 06:05 -0800
    Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-06 07:44 -0800
      Re: problem with usbtmc-communication Terry Reedy <tjreedy@udel.edu> - 2012-12-06 15:28 -0500
        Re: problem with usbtmc-communication Jean Dubois <jeandubois314@gmail.com> - 2012-12-07 05:51 -0800

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