User Manual

2400 Series SourceMeter
®
User’s Manual SCPI Command Reference 18-29
Query :UNITs? Query units for user-defined calculation
Description This command is used to specify the units suffix name for a user-
defined math calculation. Use three ASCII characters for the units
suffix name. If using fewer than three characters, add spaces to the
right of the units name in the string. For example, if the units name is
“Z,” send it as follows:
:calc:math:unit “Z ”
The units name can also be enclosed in single quotes as follows:
:calc:math:unit ‘Z’
Define math expression
[:EXPRession] <form> or [:DEFine] <form>
:CALCulate[1]:MATH[:EXPRession] <form> Define math formula
:CALCulate[1]:MATH[:EXPRession][:DEFine] <form> Define math formula
Parameters <form> = mathematical formula using instrument readings, numbers
and standard math operator symbols. See “Description” for details.
Query :MATH? Query user-defined math expression
Description Use either of these two commands to define a math formula using
measure and source readings, numeric constants, and standard
math operator symbols. After the math expression is defined, it will
be assigned to the name that was created using the :NAME com
-
mand and will become the selected math expression. See “NAME
<name>,” page 18-26 for more details.
Valid parameter names for measure and source readings include:
VOLTage Use V-Measure or V-Source reading
CURRent Use I-Measure or I-Source reading
RESistance Use ohms reading
TIME Use timestamp reading
Valid math operators and their operations are listed as follows:
+Add
- Subtract
* Multiply
/ Divide
^ Exponent
log Logarithmic, base 10
ln Natural log
sin Sine
cos Cosine
tan Tangent
exp e
x
NOTE The log and ln operations are performed on the absolute value of the speci-
fied number. For example, log (100) = 2 and log (-100) = 2.