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.