National Instruments NI-488.2 Benutzerhandbuch

© National Instruments Corporation

SRQI indicates that a GPIB device is requesting service. SRQI is set 
whenever the GPIB interface is CIC, the GPIB SRQ line is asserted, and the 
automatic serial poll capability is disabled. SRQI is cleared either when the 
GPIB interface ceases to be the CIC or when the GPIB SRQ line is 
unasserted. 

RQS appears in the status word only after a device-level call and indicates 
that the device is requesting service. RQS is set whenever one or more 
positive serial poll response bytes have been received from the device. A 
positive serial poll response byte always has bit 6 asserted. Automatic serial 
polling must be enabled (it is enabled by default) for RQS to automatically 
appear in 

ibsta

. You can also wait for a device to request service 

regardless of the state of automatic serial polling by calling 

ibwait

 with a 

mask that contains RQS. Do not issue an 

ibwait

 call on RQS for a device 

that does not respond to serial polls. Use 

ibrsp

 to acquire the serial poll 

response byte that was received. RQS is cleared when all of the stored serial 
poll response bytes have been reported to you through the 

ibrsp

 function.

CMPL indicates the condition of I/O operations. It is set whenever an I/O 
operation is complete. CMPL is cleared while the I/O operation is in 
progress.

LOK indicates whether the interface is in a lockout state. While LOK is set, 
the 

EnableLocal

 or 

ibloc

 call is inoperative for that interface. LOK is 

set whenever the GPIB interface detects that the Local Lockout (LLO) 
message has been sent either by the GPIB interface or by another 
Controller. LOK is cleared when the System Controller unasserts the 
Remote Enable (REN) GPIB line.