Table D-3 Typical Addressed Multiline Command Sequence; Table D-4 Typical Addressed Common Command Sequence; Typical Command Sequences - Keithley 2500 User Manual

D-12 IEEE-488 Bus Overview

Typical command sequences

For the various multiline commands, a specific bus sequence must take place to properly
send the command. In particular, the correct listen address must be sent to the instrument
before it will respond to addressed commands.
sending the addressed multiline commands. In this instance, the SDC command is being
sent to the instrument. UNL is generally sent as part of the sequence to ensure that no
other active listeners are present. Note that ATN is true for both the listen command and
the SDC command byte itself.
Table D-3
Typical addressed multiline command sequence
Step
*Assumes primary address = 25.
Table D-4
the instrument is being addressed, but it is set high while sending the common command
string.
Table D-4
Typical addressed common command sequence
Step
*Assumes primary address = 25.
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Command ATN state
1 UNL Set low
2 LAG* Stays low
3 SDC Stays low
4 Returns high
gives a typical common command sequence. In this instance, ATN is true while
Command ATN state
1 UNL Set low
2 LAG* Stays low
3 Data Set high
4 Data Stays high
5 Data Stays high
6 Data Stays high
Models 2500 and 2502 User's Manual
Table D-3 lists a typical bus sequence for
Data bus
ASCII Hex
? 3F
9 39
EOT 04
Data bus
ASCII Hex
? 3F
9 39
* 2A
R 52
S 53
T 54
Decimal
63
57
4
Decimal
63
57
42
82
83
84