National Instruments GPIB-MAC User Manual page 92

November 1985
tmo - Change or Disable Time Limit
tmo: Initialization function
Syntax: tmo [timeio] [ ,timesp] <CR>
Purpose: You use tmo at the beginning of your program to change
the time limits in effect on the GPIB-MAC. The time
limits prevent the GPIB-MAC from hanging indefinitely
when an error situation prevents normal completion of an
operation.
Remarks: The arguments timeio and timesp are numeric strings.
timeio specifies the amount of time in seconds the
GPIB-MAC waits for an I/O operation (rd, wrt, cmd)
or the wait function to complete. timesp specifies the
amount of time in seconds each device is given in which
to respond to a serial poll. The power-on timeouts are
10 seconds for timeio and l/10 of a second for timesp.
timeio and timesp may be any decimal number
between .OOOOl and 3600 which corresponds to time
limits between 10 microseconds and 1 hour. lO,.l
specifies a time of 10 seconds for I/O operations and
timesp may also be 0, which disables either timeout
accordingly. Neither timeio nor timesp may contain
commas (e.g., 1000 is correct but 1,000 is not).
The timeio time limit is in effect for the cmd, rd,
and wrt functions. If the GPIB-MAC cannot complete
any of these functions within the period of time set by
timeio, it aborts the function and records the EABO
error. Bytes that were transferred before the timeout are
not affected.
The timeio time limit is also the maximum amount of
time the wait function waits when you caIl it with the
81 SECTION FOUR - FUNCTIONS