Chapter 5
S Mode Functions
© National Instruments Corp.
5-3
GPIB-232CT User Manual
cac - Become Active Controller
Type:
Low-level Controller function
Syntax:
cac
[bool]
<CR>
Purpose:
You
use
cac
to change the GPIB-232CT from Standby
Controller to Active Controller when the I/O and bus
management functions do not meet the needs of your device.
cac
gives you more precise control over the GPIB than the
I/O and bus management functions.
Remarks:
If the argument
bool
is 0, the GPIB-232CT takes control
immediately; that is, it takes control asynchronously. If the
argument
bool
is 1, the GPIB-232CT takes control after any
handshake that is in progress completes; that is, it takes
control synchronously.
If you call
cac
without an argument, the GPIB-232CT returns
to you the current Controller status, which is 0 if the
GPIB-232CT is not the Active Controller and 1 if the
GPIB-232CT is the Active Controller.
If you call
cac
with an argument and the GPIB-232CT is not
CIC, the GPIB-232CT records the ECIC error.
The power-on Controller status of the GPIB-232CT is Idle
Controller.
See Also:
gts
and
sic
.
Examples:
1.
PRINT #1,"cac 0" 'Take control immediately.
2.
PRINT #1,"cac 1" 'Take control synchronously.
3.
PRINT #1,"CAC"
'Are we the Active Controller?
response: 1<CR><LF>
(...yes, we're CAC)