17-28
SCPI Command Reference
NOTE
The log and ln operations are performed on the absolute value of the specified num-
ber. For example, log (100) = 2 and log (-100) = 2.
Expressions are evaluated according to the following precedence rules:
1. Enclosed by parentheses
2. Unary operators (+ and -)
3. ^ (exponentiation)
4. * (multiplication) and / (division)
5. + (addition) and - (subtraction)
6. Left to right.
The readings used for the calculation depend on how the SourceMeter is
con
fi
gured. If con
fi
gured to Source V Measure I, the voltage reading for the
calculation will be the source value, and the current reading will be the cur-
rent measurement. Conversely, if con
fi
gured to Source I Measure V, the cur-
rent reading will be the source value, and the voltage reading will be the
voltage measurement.
Measure readings take priority over source readings. Thus, if con
fi
gured to
Source V Measure V, the voltage reading for the calculation will be the volt-
age measurement (not the programmed V-Source value). Conversely, if con-
fi
gured to Source I Measure I, the current reading for the calculation will be
the current measurement.
The result of a calculation using a reading that is not sourced or measured
will be the invalid NAN (not a number) value of +9.91e37. For example,
using a current reading in a calculation for Source V Measure V will cause a
NAN result.
Example using Source I Measure V con
fi
guration:
:calc:math (volt * curr)
Calculate power using voltage measurement
and I-Source value.
After a calculation is con
fi
gured and enabled, the results are displayed when
source-measure operations are performed. See :STATe. Use the :data? com-
mand to send the results to the computer.
Vectored math
By incorporating vectors, you select which readings to use for the math cal-
culation. After all programmed source-measure operations are completed,
the math calculation(s) are performed using readings indicated by the speci-
fi
ed vectors.
Vector numbers are enclosed in brackets ([]), and start at 0. Thus, vector 0 is
the
fi
rst reading in the array, vector 1 is the second reading in the array, and
so on. The largest vector number in the expression de
fi
nes the vector array
size.
For example, assume the SourceMeter is programmed to perform 10 source-
measure operations, and the following vectored math calculation is used:
(volt[3] - volt[9])
The above expression de
fi
nes a vector array that is made up of 10 readings.
Since the SourceMeter is programmed to perform 10 source-measure opera-
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Страница 78: ...2 14 Connections ...
Страница 98: ...3 20 Basic Source Measure Operation ...
Страница 138: ...5 30 Source Measure Concepts ...
Страница 156: ...6 18 Range Digits Speed and Filters ...
Страница 168: ...7 12 Relative and Math ...
Страница 176: ...8 8 Data Store ...
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Страница 248: ...11 22 Limit Testing ...
Страница 310: ...16 6 SCPI Signal Oriented Measurement Commands ...
Страница 418: ...17 108 SCPI Command Reference ...
Страница 450: ...18 32 Performance Verification ...
Страница 477: ...A Specifications ...
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Страница 498: ...B 10 Status and Error Messages ...
Страница 499: ...C DataFlow ...
Страница 503: ...D IEEE 488BusOverview ...
Страница 518: ...D 16 IEEE 488 Bus Overview ...
Страница 519: ...E IEEE 488andSCPI ConformanceInformation ...
Страница 523: ...F MeasurementConsiderations ...
Страница 539: ...G GPIB488 1Protocol ...
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