National Instruments NI-488.2 ユーザーズマニュアル

© National Instruments Corporation

LACS indicates whether the GPIB interface is addressed as a Listener. 
LACS is set whenever the GPIB interface detects that its listen address 
(and secondary address, if enabled) has been sent either by the GPIB 
interface itself or by another Controller. LACS is also set whenever the 
GPIB interface shadow handshakes as a result of the 

ibgts

 function. 

LACS is cleared whenever the GPIB interface detects the Unlisten (UNL) 
command, its own talk address, Interface Clear (IFC), or that the 

ibgts

 

function has been called without shadow handshake.

DTAS indicates whether the GPIB interface has detected a device trigger 
command. DTAS is set whenever the GPIB interface, as a Listener, detects 
that the Group Execute Trigger (GET) command has been sent by another 
Controller. DTAS is cleared on any call immediately following an 

ibwait

 

call, if the DTAS bit is set in the 

ibwait

 mask parameter.

DCAS indicates whether the GPIB interface has detected a device clear 
command. DCAS is set whenever the GPIB interface detects that the 
Device Clear (DCL) command has been sent by another Controller, or 
whenever the GPIB interface as a Listener detects that the Selected Device 
Clear (SDC) command has been sent by another Controller. 

If you use the 

ibwait

 or 

ibnotify

 function to wait for DCAS and the 

wait is completed, DCAS is cleared from 

ibsta

 after the next NI-488.2 

call. The same is true of reads and writes. If you call a read or write function 
such as 

ibwrt

 or 

Send

, and DCAS is set in 

ibsta

, the I/O operation is 

aborted. DCAS is cleared from 

ibsta

 after the next NI-488.2 call.