SME Structure and Syntax of the Messages
1038.6002.02 3.9 E-13
3.5.5 Parameter
Most commands require a parameter to be specified. The parameters must be separated from the
header by a "white space". Permissible parameters are numerical values, Boolean parameters, text,
character strings and block data. The type of parameter required for the respective command and the
permissible range of values are specified in the command description (see Section 3.6).
Numerical values Numerical values can be entered in any form, i.e. with sign, decimal point and
exponent. Values exceeding the resolution of the instrument are rounded up or
down. The mantissa may comprise up to 255 characters, the exponent must lie
inside the value range -32000 to 32000. The exponent is introduced by an "E"
or "e". Entry of the exponent alone is not permissible. In the case of physical
quantities, the unit can be entered. Permissible unit prefixes are G (giga), MA
(mega), MOHM and MHZ are also permissible), K (kilo), M (milli), U (micro)
and N (nano). It the unit is missing, the basic unit is used.
Example: SOURce:FREQuency 1.5 kHz = SOURce:FREQuency 1.5E3
Special numerical The texts MINimum, MAXimum, DEFault, UP and DOWN are interpreted as
values special numerical values.
In the case of a query, the numerical value is provided.
Example: Setting command: SOURce:VOLTage MAXimum
Query: SOURce:VOLTage? Response: 15
MIN/MAX MINimum and MAXimum denote the minimum and maximum value.
DEF DEFault denotes a preset value which has been stored in the EPROM. This
value conforms to the default setting, as it is called by the *RST command.
UP/DOWN UP, DOWN increases or reduces the numerical value by one step. The step
width can be specified via an allocated step command (see annex C, List of
Commands) for each parameter which can be set via UP, DOWN.
INF/NINF INFinity, Negative INFinity (NINF) represent the numerical values -9.9E37 or
9.9E37, respectively. INF and NINF are only sent as device responses.
NAN Not a Number (NAN) represents the value 9.91E37. NAN is only sent as device
response. This value is not defined. Possible causes are the division of zero by
zero, the subtraction of infinite from infinite and the representation of missing
values.
Boolean Parameters Boolean parameters represent two states. The ON state (logically true) is
represented by ON or a numerical value unequal to 0. The OFF state (logically
untrue) is represented by OFF or the numerical value 0. 0 or 1 is provided in a
query.
Example: Setting command: SOURce:FM:STATe ON
Query: SOURce:FM:STATe? Response: 1
Text Text parameters observe the syntactic rules for key words, i.e. they can be
entered using a short or long form. Like any parameter, they have to be
separated from the header by a white space. In the case of a query, the short
form of the text is provided.
Example: Setting command: OUTPut:FILTer:TYPE EXTernal
Query: OUTPut:FILTer:TYPE? Response: EXT
Strings Strings must always be entered in quotation marks (’ or ").
Example: SYSTem:LANGuage "SCPI" or
SYSTem:LANGuage ’SCPI’
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