User manual

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. Table E-3 lists a typical bus
sequence for 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 E-4 gives a typical common command sequence. In this instance, ATN is true while
the instrument is being addressed, but it is set high while sending the common command
string.
Table E-3
Typical addressed command sequence
Step Command ATN state
Data bus
ASCII Hex Decimal
1
2
3
4
UNL
LAG*
SDC
Set low
Stays low
Stays low
Returns high
?
0
EOT
3F
30
04
63
48
4
*Assumes primary address = 16.
Table E-4
Typical addressed command sequence
Step Command ATN state
Data bus
ASCII Hex Decimal
1
2
3
4
5
6
UNL
LAG*
Data
Data
Data
Data
Set low
Stays low
Set high
Stays high
Stays high
Stays high
?
0
*
R
S
T
3F
30
2A
52
53
54
63
48
42
82
83
84
*Assumes primary address = 16.
2000-900 (J - Aug 2010) BOOK.fm Page 13 Wednesday, October 12, 2011 12:29 PM