Keithley 194 Instruction Manual page 106

IEEE-466 PROGRAMMING
Multiple Commands
A number of commands can be grouped together in one
command string, which is generally terminated by the "X"
character. This character tells the instrument to execute the
command or command string, as described in paragraph
4.9.1. Commands sent without the execute character will
not be executed at that particular time, but they will be
stored within an internal command buffer for later execu-
tion when the execute character is finally received. Note,
however, that multiple commands using the same com-
mand letter and contained within one string must each
be terminated with X as in this example: 04,6X05,5X
Invalid Commands
If an invalid command is sent as part of the command
string, that command will not be executed (valid com-
mands in the string will be executed, however). Under
these conditions, the instrument may or may not display
a front panel error message (IDDC or IDDCO), as covcrcd
in paragraph 4.7, and it can be programmed to generate
an SRQ (Service Request), as discussed in paragraph 4.9.16.
NOTE
The instrument does not check the validity of com-
mands until the X character is received.
Some typical examples of valid command strings include:
ROX Single command string.
RlIOPlX Multiple command string.
Q 1X Space is ignored
NO,lOOX Dual-parameter command string (parameters
separated by comma)
S0/250E-6X dual-parameter command delimited by i.
Typical invalid command strings include:
E1X Invalid command, as E is not one of the instrument's
valid commands.
Y65X Invalid command option because 65 is not an op-
tion of the Y command.
NOlOOE-6X Dual parameter command without the
necessary separating comma or other legal delimiter.
The list below details which device-dependent commands
will generate the IDDCO error message, and those com-
mands which incorporate auto bounding. Auto bounding
is when the unit automatically changes the option to
within the valid range. For example, LJZOX will be changed
to UlZX, while U-IX will be changed to UOX.
Device-Dependent
Command(s)
I, F, 6 T L M D
Qr P, 1, A
G
K
H
F
1:
R
s
N
w
L
Y
0
Action
No IDDCO, no autobound
No IDDCO, autobound O-2
No IDDCO, autobound O-7
No IDDCO, autobound O-3
No IDDCO, autobound O-38
No IDDCO, autobound
No IDDCO, 2-8 gives NO SCAN-
NER, 12 gives NO A/D IN CE12
No IDDCO, no autobound, 20, 21
give NO AID in CH2, if ap-
propriatc. 9-19 are ignored.
No IDDCO, 12 disables autorange,
other values autobounded O-3.
No IDDCO, freq converted to time
(if appropriate) then autobounded
'IpXC-lSE!C.
No IDDCO, time converted to
#samples (if appropriate), then
autobounded l-65,535.
No IDDCO, time converted to
#samples (if appropriate), then
autobounded 32,76%10' (lb-bit),
65,536-10 (a-bit)
No IDDCO, autobound first
parameter O-5 autobound second
parameter -25OV to +25OV.
IDDCO if not valid terminator, no
autobound.
No IDDCO, first parameter 0, 1, 9
(no second) parameter. First
parametcr~~?-8, (no autobound).
Device-Dependent Command Summary
Device-dependent commands that control the Model 194
are summarized in Table 4-8, which also lists the pertinent
paragraph where each command is covered in detail. As
listed, all command letters are in upper-case format;
however, you can substitute corresponding lower-case let-
ters, if desired. For example, you can use rlX in place of
RlX.
NOTE
The X (execute) character must be in upper case.
Note that you can also use the translator mode to
customize your programming language. The translator
mode is discussed in detail in paragraph 4.10.
4-16