November 1985
National Instruments
The GPIB commands, or interface messages, are listed
in Appendix A. They include device talk and listen
addresses, secondary addresses, messages, device clear
and trigger instructions, and other management
messages.
Do not use cmd to send programming instructions to
devices. Use
rd
and wrt to send or receive device
programming instructions and other device dependent
information.
The cmd operation terminates when:
the GPIB-MAC successfully transfers all commands,
the GPIB-MAC detects an error (GPIB-MAC is not
the
I/O
time
is exceeded,
the Take Control
command is in your
command string and is sent to the GPIB.
the Interface Clear
message is received from
System Controller (not the GPIB-MAC).
After cmd terminates, the GPIB-MAC records the
number of command bytes it actually sent. If an event in
the above list occurs, the count may be less than
expected
If you specify #count and enter more than #count
command bytes, the excess command bytes up to the
are discarded.
If you call cmd and the GPIB-MAC is not CIC, the
records the ECIC error.
36
SECTION
FUNCTIONS