/ 
Lab-Measurement-3.512
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/ Lab::Bus::USBtmc

NAME

Lab::Bus::LinuxGPIB - LinuxGPIB bus

SYNOPSIS

This is the USB TMC (Test & Measurement Class) bus class.

my $tmc = new Lab::Bus::USBtmc({ });

or implicit through instrument and connection creation:

my $instrument = new Lab::Instrument::HP34401A({
  connection_type => 'USBtmc',
  tmc_address=>1,
}

DESCRIPTION

Driver for the interface provided by the usbtmc linux kernel module.

Obviously, this will work for Linux systems only. On Windows, please use Lab::Bus::VISA. The interfaces are (errr, will be) identical.

Note: you don't need to explicitly handle bus objects. The Instruments will create them themselves, and existing bus will be automagically reused.

CONSTRUCTOR

new

my $bus = Lab::Bus::USBtmc({
 });

Return blessed $self, with @_ accessible through $self->config().

Thrown Exceptions

Lab::Bus::USBtmc throws

Lab::Exception::TMCOpenFileError

Lab::Exception::CorruptParameter

METHODS

connection_new

$tmc->connection_new({ tmc_address => $addr });

Creates a new connection ("instrument handle") for this bus. The argument is a hash, whose contents depend on the bus type. For TMC at least 'tmc_address' is needed.

The handle is usually stored in an instrument object and given to connection_read, connection_write etc. to identify and handle the calling instrument:

$InstrumentHandle = $GPIB->connection_new({ gpib_address => 13 });
$result = $GPIB->connection_read($self->InstrumentHandle(), { options });

See Lab::Instrument::Read().

connection_write

$GPIB->connection_write( $InstrumentHandle, { Cmd => $Command } );

Sends $Command to the instrument specified by the handle.

connection_read

$GPIB->connection_read( $InstrumentHandle, { Cmd => $Command, ReadLength => $readlength, Brutal => 0/1 } );

Sends $Command to the instrument specified by the handle. Reads back a maximum of $readlength bytes. If a timeout or an error occurs, Lab::Exception::GPIBError or Lab::Exception::Timeout are thrown, respectively. The Timeout object carries the data received up to the timeout event, accessible through $Exception->Data().

Setting Brutal to a true value will result in timeouts being ignored, and the gathered data returned without error.

timeout

$GPIB->timeout( $connection_handle, $timeout );

Sets the timeout in seconds for GPIB operations on the device/connection specified by $connection_handle.

config

Provides unified access to the fields in initial @_ to all the child classes. E.g.

$GPIB_Address=$instrument->config(gpib_address);

Without arguments, returns a reference to the complete $self->config aka @_ of the constructor.

$config = $bus->config();
$GPIB_PAddress = $bus->config()->{'gpib_address'};

CAVEATS/BUGS

Sysfs settings for timeout not supported, yet.

SEE ALSO

AUTHOR/COPYRIGHT

Copyright 2004-2006 Daniel Schröer <schroeer@cpan.org>, 
          2009-2010 Daniel Schröer, Andreas K. Hüttel (L<http://www.akhuettel.de/>) and David Kalok,
          2010      Matthias Völker <mvoelker@cpan.org>
          2011      Florian Olbrich, Andreas K. Hüttel
          2012      Hermann Kraus

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.