Agilent Technologies USB/GPIB Interface Converter 82357A, Руководство пользователя

Страница: 40 / 70

40 Chapter 2
Using the 82357A
Setting Configuration Parameters
Changing Modes of Operation
If your system has multiple 82357As configured (multiple mode of
operation), the
only
way to change from multiple mode of operation back to
the single mode of operation is:
1
Unplug all 82357As from the system.
2
Run Connection Expert (click the blue IO icon and click
Agilent
Connection Expert
).
3
Delete all 82357A configurations by selecting each USB/GPIB icon in
the explorer view and clicking
Delete
(or delete all except one
configuration).
4
Reattach and reconfigure a single 82357A.
Setting Timeout Floor Values
The 82357A has a default timeout “floor” value that is an internal
requirement to ensure reliable USB communication. The 82357A will not
allow timeouts LESS than the floor value. (By default, VISA/SICL timeouts
are set to an infinite time.)
To programmatically determine the timeout floor, you can set the timeout to
a very small value, such as 1 msec, and then query for the actual timeout
floor value. VISA and SICL examples follow.
Example: Query
Timeout Floor
(VISA)
tval = 1; // Try to set timeout to 1 msec
err = viSetAttribute(id, VI_ATTR_TMO_VALUE, tval_in);
...
err = viGetAttribute(id, VI_ATTR_TMO_VALUE, &tval_out);
...
printf("Set timeout to [%d], actual timeout that resulted [%d]\n",
tval_in, tval_out );
Example: Query
TimeOut Floor
(SICL)
tval = 1; // Try to set timeout to 1 msec
err = itimeout(id, tval_in);
...
err = igettimeout(id, &tval_out);
...
printf("Set timeout to [%d], actual timeout that resulted [%d]\n",
tval_in, tval_out );