MDO3000 Programmer Manual.pdf - 第66页
Command Groups Measurement C ommand Group Use the commands in the Measurement Co mmand Group to control the automated measurement system. Up to eight automated measurements can be displayed on the screen. In the commands…
Command Groups
Math Command G
roup
Use the commands in the Math Command Group to create and define a
math waveform. First, specify the math type using MATH[1]:TYPe – either
dual wavefor
m, FFT, advanced math, or spectrum math. Then, using the
MATH[1]:DEFine command, you can build simple math expressions that
contain no computation, such as
:MATH:DEFine CH1. You can also build
complex expressions that consist of up to 128 characters in a quoted string,
and comprise many sources, functions, and operands, such as
:MATH:DEFINE
"SINE(CH1)*(VAR1+CH2)*CH3 - CAREA(C H4)".
Note that when your program updates a live waveform or alters a reference
waveform, the math waveforms containing those waveforms as sources are also
updated
to reflect the changes.
NOTE. If you set the math type to
FFT
, your math expression can only be the
FFT of a live analog or reference waveform. However, if the math type is set
to
ADVanced
, then you can include FFT as part of a math expression. See the
examples of advanced math in MATH[1]:DEFine for more information.
Table 2-32: Math Commands
Command
Description
MATH[1]? Returns the definition of the m ath w aveform
MATH[1]:AUTOSCale Sets (or queries) the state o f automatic vertical scaling of the math waveform.
MATH[1]:DEF ine
This command specifies the current math function as a text string.
MATH[1]:HO Rizontal:POSition This command specifies the math horizontal display position for FFT or (non-live) math
reference waveforms
MATH[1]:HO Rizontal:SC Ale This command specifies the math horizontal display scale for FFT or for Dual Math
waveforms
MATH[1]:HORizontal:UNIts Returns the math waveform horizontal unit value
MATH[1]:LABel
Sets or queries the waveform label for the math waveform
MATH[1]:SPECTral:MAG This command speci fies the units of spectral magnification in the math string
MATH[1]:SPECTral:WINdow This command specifies the window function for math waveform spectral input data
MATH[1]:TYPe
This command specifies the math waveform type (
DUAL, FFT, ADVanced or
SPECTRUM
). This command is used along with MATH :DEFine.
MATH[1]:VERTical:POSition This command specifies the vertical position of the currently selected math type
MATH[1]:VERTical:SCAle This command specifies the vertical scale of the currently selected math type
MATH[1]:VERTical:UNIts
Returns the math wav e form vertical units
MATHVAR?
Returns all numerical values used within math expressions
MATHVAR:VAR<x>
This command specifies numerical values you can use within math expressions
MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-35
Command Groups
Measurement C
ommand Group
Use the commands in the Measurement Command Group to control the automated
measurement system.
Up to eight automated measurements can be displayed on the screen. In the
commands, these measurement readouts are named MEAS<x>, where <x> is the
measurement number.
In addition to the eight displayed measurements, the measurement commandslet
you specify an additional measurement, IMMed. The immediate measurement
has no front-panel equivalent. Immediate measurements are never displayed.
Because they are computed only when needed, immediate measurements slow the
waveform update rate less than displayed measurements.
To obtain measurement results, use the MEASUrement:MEAS<x>:VALue?
query for displayed results or the MEASUrement:IMMed:VALue? query for
immediate measurements.
Measurement commands can set and query measurement parameters. You
can assign some parameters, such as waveform sources, differently for each
measurement. Other parameters, such as reference levels, have only one value,
which applies to all measurements.
Readout values for t
he 8 displayed measurements are updated periodically. As
such, queries of these measurement values may return 9.91E+37, which represents
NaN (not a number) and a measurement warning event (e.g. 2225. “Measurement
error. No waveform to measure”) when the measurement is not yet computed.
Immediate measurement queries will return values once the measurement has
been computed.
Example of Immediate
Measurements
An example command sequence follows that illustrates immediate measurements
of Cycle Mean on channel 1:
:MEASUrement:IMMed:SOUrce1 CH1
:MEASUrement:IMMed:TYPe CMEan
:MEASUrement:IMMed:VALue? -18.5568E-3
:MEASUrement:IMMed:VALue?;VALue?;VALue?
-21.6400E-3;-23.8023E-3;-21.0064E-3
Table 2-33: Measurement Commands
Command
Description
MEASUrement?
Returns all measurement parameters
MEASUrement:CLEARSNapshot
Removes the measurement snapshot display
MEASUrement:GATing This command specifies the measurement gating
MEASUrement:IMMed?
Returns all immediate measurement setup parameters
2-36 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual
Command Groups
Table 2-33: Measurement Commands (cont.)
Command
Description
MEASUrement:IMMed:DELay? Returns information about the immediate delay measurement
MEASUrement:IMMed:DELay:
DIRection
This command specifies the search direction to use for immediate delay measurements
MEASUrement:IMMed:DELay:
EDGE<x>
This command specifies the slope of the edge used for immediate delay “from” and “to”
waveform measurements
MEASUrement:IMMed:SO Urce<x> This command specifies the “from” source for all single channel immediate measurements
This command specifies the source to measure “to” for two-channel measurements
MEASUrement:IMMed:TYPe This command specifies the type of the immediate measurement
MEASUrement:IMMed:UN Its? Returns the units of the i mmediate measurement
MEASUrement:IMMed:VALue? Returns the value of the immediate measurement
MEASUrement:INDICa tors?
Returns all measurement indicator parameters
MEASUrement:INDICa tors:
HORZ<x>?
Returns the position of the specified horizontal measurement indicator
MEASUrement:INDICa tors:
NUMHORZ?
Returns the number of horizontal measurement indicators currently being displayed
MEASUrement:INDICa tors:
NUMVERT?
Returns the number of vertical measurement indicators currently being displayed
MEASUrement:INDIC ators:STATE This command specifies the state of visible m easurement indicators
MEASUrement:INDICa tors:
VERT<x>?
Returns the value of the specified vertical measurement indicator
MEASUrement:MEAS<x>?
Returns all measurement parameters
MEASUrement:MEAS<x>:COUNt? Returns the number of values accumulated since the last statistical reset
MEASUrement:MEAS<x>:DELay? Returns the delay measurement parameters for the specified measurement
MEASUrement:MEAS<x>:DELay:
DIRection
This command specifies the search direction to use for delay measurements
MEASUrement:MEAS<x>:DELay:
EDGE<x>
This command specifies the slope of the edge to use for delay “from” and “to” waveform
measurements
MEASUrement:MEAS<x>:
MAXimum?
Returns the maximum value found since the last statistical reset
MEASUrement:MEAS<x>:MEAN?
Returns the mean value accumulated since the last statistical reset
MEASUrement:MEAS<x>:
MINImum?
Returns the minimum value found since the last statistical reset
MEASUrement:MEAS<x>:
SOUrce<x>
This command specifies the “from” source for all single channel immediate measurements
This command specifies the source to measure “to” for two-channel measurements
MEASUrement:MEAS<x>:STATE This command specifies whether the specified measurement slot is computed and displayed
MEASUrement:MEAS<x>:STDdev? Returns the standard deviation of values accumulated since the last statistical reset
MEASUrement:MEAS<x>:TYPe This command specifies the measurement<x> type
MEASUrement:MEAS<x>:UNIts?
Returns measurement<x> units
MEASUrement:MEAS<x>:VALue? Returns the value of measurement<x>
MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-37