Keithley 7001, Instruction Manual, Page: 338 / 353

IEEE-488 Bus Overview
D-9
Table D-4
Typical common command sequence
Data bus
Step Command ATN state ASCII Hex Decimal
1 UNL Set low ? 3F 63
2 LAG* Stays low ’ 27 39
3 Data Set high * 2A 42
4 Data Stays high R 52 82
5 Data Stays high S 53 83
6 Data Stays high T 54 84
Assumes primary address = 7.
Table D-5
IEEE command groups
HANDSHAKE COMMAND GROUP
NDAC = NOT DATA ACCEPTED
NRFD = NOT READY FOR DATA
DAV = DATA VALID
UNIVERSAL COMMAND GROUP
ATN = ATTENTION
DCL = DEVICE CLEAR
IFC = INTERFACE CLEAR
REN = REMOTE ENABLE
SPD = SERIAL POLL DISABLE
SPE = SERIAL POLL ENABLE
ADDRESS COMMAND GROUP
LISTEN LAG = LISTEN ADDRESS GROUP
MLA = MY LISTEN ADDRESS
UNL = UNLISTEN
TALK TAG = TALK ADDRESS GROUP
MTA = MY TALK ADDRESS
UNT = UNTALK
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