                   FASTER VOLTMETER CONTROL WITH FIREWIRE
                   --------------------------------------



     The hpe132632v.dll driver, which controls both the HP E1326 and
the HP E1411 voltmeters, has been improved to provide better
performance.  There are new commands which need to be turned on so as
to not change the expectations of existing code. The commands that are
available in the voltmeter to improve performance are:


     DIAGnostic:INTerrupt[:LINE] <card_number>,<line>
          This is an existing command with a new recommended use.  It
       can be used with the HP E8460 or HP E8462 switch card.  The
       <card_number> ranges from 1 to the number of switch cards that
       are commanded by the voltmeter.  The <line> ranges from 0
       through 7.  Normally the line is defaulted to 1.  This means
       that the voltmeter will command the switch to close, then
       suspend operation until the interrupt tells it that the switch
       is ready.  This makes the switch an voltmeter a "bus friendly"
       system -- a multi-tasking computer is free to do other things
       while waiting for the mechanical switch to move.  However, it
       only takes the HP E8460 0.5 milli-seconds to open or close a
       switch.  An interrupt takes well over a millisecond to process
       on any platform.  By setting the interrupt line to 0,
       HP E8460|E8462 switch card interrupts will be disabled.  The
       voltmeter will then wait in a loop, polling the switch card
       until it is ready.  This will allow the voltmeter to respond
       much faster, but it will also hog the interface and VXI
       backplane in the process.

     DIAGnostic:INTerrupt:SYSTem OFF|ON
          This is a new command for the voltmeter.  The default mode
       is ON, unless the voltmeter is running under a interface that
       does not support interrupts.  Normally, when the voltmeter is
       being programmed by a command that may take a few milli-seconds,
       an interrupt is used to to indicate when the instrument is ready
       for another command.  As with "DIAG:INT" above, this makes the
       voltmeter "bus friendly", but slower to respond to its own needs. 
       Turning "DIAG:INT:SYST OFF" will disable the use of interrupts --
       using polling instead of interrupts to determine when the
       voltmeter is ready.  If the hpe132632v.dll determines that the
       Firewire interface is being used, the query form of this command
       will return a 2 instead of a 1 to indicate that the mode is ON. 
       In this case, some of the interrupts will automatically be
       replaced with a poll-status -- yield loop.  This will prevent
       problems with interrupts while at the same time making the driver
       more friendly if there is another process running on the computer.
