Keithley 486 Instruction Manual page 87

SECTION 4
IEEE-488 Reference
within an internal command buffer for later execution
when the execute character is tially received.
Invalid Commands - If an invalid command is sent as
part of the command string, no co mmands in the string
will be executed. Under these conditions, the instrument
will display a front panel error message (IDDC or ID-
DCO) and it can be programmed to generate an SRQ
(ServiceRequest),asdiscussedinparagraph4.2.11.Com-
mands are checked es they are received. When an illegal
command is received, all other commands since the pre-
vious X and until the next X are ignored.
Some typical examples of valid co nunand strings in-
clude:
ROX
Single command followed by execute com-
mend.
Y4SOPOX Multiple command string.
21X
Space is ignored
v4,o,ox
Multiple-option co mmand string (options
separated by commas).
Typical invalid command strings include:
ElX Invalid command, as E is not one of the in-
strument's valid commands.
K6X
Invalid command option because 6 is not an
option of the K commend.
N600X
Invalid parameter (buffer size cannot exceed
512).
22.001X Multiple-option command
without the nec-
essary separating commas.
Device-dependent Command Summary - All Model
486/487 device-dependent commands are summarized
inTable4-1,whichalsolistsrespectiveparagraphswhere
more detailed information on each command may be
found.
Mode
Display Intensity
Table 4-l. Device-dependent Command Summary
Command Description
A0
Normal display
z
Dim display
Turn display off
PU&
4.2.1
Reading Source
Zero Check
and Correct
BO
Bl
B2
83
B4
co
::
Readings from A/D
single reading from data store
All readings from data store
Mexirnum reading from data store
Minimum reading from data store
Disable zero check
Enable zero check
Enable zero check and perform zero correction
4.2.2
4.2.3
Display
V/I ohms
Data Format
Da
D
FO
Fl
GO
;:
G3
G4
GS
Display up to 18 character (a) message
4.2.4
Cancel display mode
Disable V/I ohms
4.2.5
Enable V/I ohms
ASClIrdgstithprefiv
4.2.6
ASCII rdgs without prefix
ASCII rdgs and buffer locations with prefix
ASCII rdgs and buffer locations without prefix
Binary rdgs: IEEE Std 754 single-precision, bytes reversed for Intel
CPUS
Binary rdgs: IEEE Std 754 single-precision, bytes in normal order for
Motorola CMJs