Section 3: Functions and features
Model 2450 Interactive SourceMeter® Instrument Reference Manual
3-6
2450-901-01 Rev. B/September 2013
Calculations that you can apply to measurements
The Model 2450 has three built-in math calculations:
•
mx+b
•
percent
•
reciprocal (1/X)
Math calculations are applied to the input signal after relative offset and before limit tests. For more
detail on the order of operations, see
(on page 3-9).
Math operations apply to the selected measurement function. If you change the measurement
function, the math operation for that measurement function becomes active.
mx+b
The mx+b math operation lets you manipulate normal display readings (x) mathematically according
to the following calculation:
mx + b = Y
Where:
•
m
is a user-defined constant for the scale factor
•
x
is the measurement reading (if you are using a relative offset, this is the measurement with
relative offset applied)
•
b
is the user-defined constant for the offset factor
•
Y
is the displayed result
When the mx+b math operation is active, the unit of measure for the front-panel voltage and current
readings is
X
and the MATH indicator is displayed to the right of the measurement. For resistance
readings, the units of measure do not change. You cannot change this units designator.
Percent
The percent math function displays measurements as percent deviation from a specified constant.
The percent calculation is:
Where:
•
Percent:
The result
•
Input:
The measurement (if relative offset is being used, this is the relative offset value)
•
Reference:
The user-specified constant
The result of the percent calculation is positive when the input is more than the reference. The result
is negative when the input is less than the reference.
When the percent operation is active, the unit of measure for the front-panel voltage and current
readings is
%
and the MATH indicator is displayed to the right of the measurement. For resistance
readings, the units of measure do not change. You cannot change this unit's designator.
