National Instruments GPIB-PC - Manual (Page 63)

GPIB-PC Functions — Overview Section Four
GPIB-PC User Manual 4-2 ©National Instruments Corp.
Status Word
All functions return a status word containing information about the state
of the GPIB and the GPIB-PC. You should test for the conditions
reported in the status word to make decisions about continued
processing. The status word is returned in the variable
IBSTA .
The status word contains 16 bits, of which 14 are meaningful. A bit
value of 1 indicates the corresponding condition is in effect. A bit value
of zero indicates the condition is not in effect.
Table 4.1 lists the conditions and the bit position to be tested for that
condition. Some bits are set only on device function calls (d); some
bits are set only on board function calls (b); and some bits are set on
either type (db).
Table 4.1 - Status Word Layout
Mnemonics Bit Hex Function Description
Pos. Value Type
ERR 15 8000 db GPIB error
TIMO 14 4000 db Time limit exceeded
END 13 2000 db END or EOS detected
SRQI 12 1000 b SRQ interrupt received
RQS 11 800 d Device requesting
service
CMPL
8 100 db I/O completed
LOK 7 80 b Lockout State
REM 6 40 b Remote State
CIC 5 20 b Controller-In-Charge
ATN 4 10 b Attention is asserted
TACS 3 8 b Talker
LACS 2 4 b Listener
DTAS 1 2 b Device Trigger State
DCAS 0 1 b Device Clear State
A description of each status word and its condition follows.