GMC-I Messtechnik GmbH
3
1.2.1.2 Keyword Conventions
The short form part of each keyword is emphasized in boldface
uppercase letters to help you remember it.
•
TRIGger
•
IMMediate
•
RESistance
•
SHORt
The SCPI parser is not sensitive to case. It will accept Trig, trig,
trigger, TRIGGER, etc. Regardless of which form you use, the
load only recognizes the accurate long form and short form. For
example, RESI or TRI will not be recognized as the right com-
mand.
1.2.2
Separators
The colon “ : ” is used to separate the keywords of two adjacent
levels in command tree. For example: “INPut:PROTection:CLEar”.
The colon “:” can be regarded as the first character of the com-
mand to indicate this command is a root command.
The space “ ” is used to separate the command and the parame-
ter.
The semicolon is used to separate multiple commands without
changing the level of the present commands. For example:
CURR:PROT:LEV 3;DEL 10. This command is equivalent of the
following two commands:
CURR:PROT:LEV 3
CURR:PROT:DEL 10
Using semicolon and colon properly can simplify the description
of command level. e.g. CURR 25;:VOLT 50. Please note that the
maximum length of a command should not exceed 100 bytes. If a
command exceeds this length, it will be given up by the load and
a remote error “-521 Input buffer overflow” will occur.
The comma “,” is used to separate multiple parameters.
1.2.3
Parameters
Parameters are data values or character strings, which follow
behind certain keywords, and are separated by spaces from key-
words.
1.2.3.1 Parameter Formats
The parameters formats have numerical data format, character
data format and Bool format etc. The character format and Bool-
ean format are similar to the keywords format, such as: ON, OFF
and CONTinuos. All parameters are ASCII. See the list 1-1 for
Parameter Formats.
List1-1 Parameter Formats
1.2.3.2 Data Unit
Numeric data may be followed by the unit. When no unit follows
the numeric data, the data unit is the standard unit of this com-
mand. See list1-2 for Data Unit, and see list 1-3 for Most-Used
Unit Multipliers.
List1-2 Data Unit
List1-3 Most-Used Unit Multipliers
1.2.4
Terminators
The command string sent to the load must be terminated by a
<new line> symbol (carriage return character). IEEE-488 EOI (End
Or Identify) can be regarded as <new line> symbol to be the ter-
minator of the command. It is acceptable if there is a <new line>
symbol after the <carriage return character>.
1.3
Examples
1.3.1
Simple Command Statements
The simple command statement consists of a command, or key-
word, usually followed by a parameter:
VOLT 25
CURR 50
TRIG
1.3.2
Compound Command Statements
When two or more keywords are connected by colons, it creates
a compound command statement. Usually, the last keyword is
followed by a parameter, and is separated by a space:
VOLT:SLEW 1000
CURR:RANG 6
TRIG:SOUR BUS
If the compound command statement contains “[“,”]”, the keyword
of this part is dispensable.
CURRent:LEVeI:TRIGgered 0.5
CURRent:TRIGgered 0.5
These two commands are the same.
1.3.3
Simple Command Queries
The simple command query consists of a keyword followed by a
question mark (?):
VOLT?
CURR?
1.3.4
Compound Command Queries
When two or more keywords are connected by colons and fol-
lowed by a question mark (?), it creates a compound query state-
ment.
VOLT:TRIG?
CURR:PROT?
MEAS:POW?
Symbol
Description
Example
< NRl>
Digits with no decimal point.
The decimal point is as-
sumed to be to the right of
the least-significant digit.
2730, 02730
< NR2>
Digits with a decimal point. 27.30, .02730
。
< NR3>
Digits with a decimal point
and an exponent.
2.730 E+2, 2.730E-2
< NRf>
Flexible decimal form that
includes NR1 or NR2 or
NR3.
2730, 27.30, 2.730E+2
。
< NRf+>
Expanded decimal form that
includes NRf and NRf and
MIN, MAX. MIN and MAX
are the minimum and maxi-
mum limit values for the pa-
rameter.
2730, 27.30, 2.730E-2,
MIN, MAX
< Bool>
Bool data
ON|OFF
< crd >
Character data
CV
< aard >
Return ASCII data. It`s al-
lowed to return undelimited
7-bit ASCII. This data type is
an implied terminator.
Class
Preferred Unit
Secondary Unit
Referenced Unit
Current
A
Ampere
Resistance
OHM
Ohm
MOHM
Megohm
Time
s
Second
Amplitude
v
Volt
Power
w
Watt
Multiplier
Mnemonic
Definition
1E6
MA
Mega
1E3
K
Kilo
1E-3
M
milli
1E-6
U
micro
1E-9
N
nano