MDO3000 Programmer Manual.pdf - 第126页

Command Groups <binary data> i s the binary data which should be exactly N-Digits bytes in length. NOTE. I fy o uw o u l dl i k et os a v eo rr e c a l law a v e f o r mt oo rf r o ma ﬁ le, use the SA V e:W A VEfor…

Command Groups

Table 2-43: Video Picture Commands (cont.)

Command Description

VIDPic:LOCation:OFFSet Sets (or queries) the video picture line-to-line offset. This is the amount of

additional delay time to add between lines of the video picture.

VIDPic:LOCation:STARt:LINE Sets (or queries) the video picture starting l ine number.

VIDPic:LOCation:STARt:PIXel Sets (or queries) the video picture starting pixel in each line

VIDPic:LOCation:WIDth Sets (or queries) the video picture width, in columns.

VIDPic:LOCation:X Sets (or queries) the video picture X origin location, in columns.

VIDPic:LOCation:Y Sets (or queries) the video picture Y origin location, in rows.

VIDPic:SOUrce Sets (or queries) the channel to use for the video picture source waveform.

VIDPic:STANdard Sets (or queries) which video picture standard to use (either NTSC or PAL).

Wa veform Transfer Command Group

(See Table 2-48.)

The

CURVe and other commands and queries in the Waveform Transfer Command

Group are used to transfer waveform data points to and from the oscilloscope.

Thewaveformdatapointsareacollectionofvaluesthatrepresenttheamplitude

of the waveform samples. One data value usually represents one data point inthe

veform record. Only one waveform can be transferred at a time.

Each waveform you transfer has an associated waveform preamble, which

ontains information such as data format, horizontal scale, vertical scale, and the

other settings in effect when the waveform was created. When you transfer a

waveform, you need to specify at least some of the general and preamble settings

(using the

DATa, WF MInpre or WFMOutpre commands) before you specify the

raw data point information (using the

CURVe command or query.)

Waveform data can be transferred to or from the oscilloscope using the Ethernet

or USBTMC interfaces in binary or ASCII format. Binary data transfer is

considerably more efﬁcient than ASCII data transfer. Binary data is transferred to

and from the oscilloscope using the IEEE488.2 arbitrary block format (7.7.6 of

the IEEE488.2 spec) which we refer to in this document as “binary block format”.

A binary block is represented as:

#N<N-Digits><binary data>

Where:

The “#” is the arbitrary block token.

N is a single hexadecimal digit specifying how many decimal digits

immediately follow.

<N-Digits> is a decimal number N digits long, that speciﬁes the number of

binary data bytes to follow.

MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-95

Command Groups

<binary data> i

s the binary data which should be exactly N-Digits bytes in

length.

NOTE. Ifyouwouldliketosaveorrecallawaveformtoorfromaﬁle, use the

SAVe:WAVEform and RECAll:WAVEform commands.

Transferring a Waveform

from an Oscilloscope to a

Computer

Use the DATa commands and WFMOutpre commands to specify the attributes of

the waveform being transferred from the oscilloscope. You must, at a minimum,

specify the waveform source (using the

DATa:SOUrce command) and data format

(using the

DATa:ENCdg and DATa:WIDth commands).

Then, use the

WFMOutpre? query, which provides the context needed to interpret

the waveform data points. Finally, use the

CURVE? query to transfer the waveform

data points. (You can also use the

WAVFrm? query, which concatenates the

WFMOutpre? and CURVe? queries. )

NOTE. In order to guarantee that the waveform data returned from

CURVE?

queries of multiple waveforms are correlated to the same acquisition, you

should use single sequence acquisition mode to acquire the waveform data

from a single acquisition. Single sequence acquisition mode is enabled using

ACQuire:STOPAfter

SEQuence

NOTE. The

WFMOutpre:BYT _Nr

and

WFMOutpre:BIT _Nr

settings are

directly related; setting one causes the other to be set accordingly. For

example,

WFMOutpre:BY T_Nr 2

causes

WFMOutpre_B IT_Nr

to be set to

16 (2 * 8 bits/byte). Similarly, setting

WFMOutpre: BIT_Nr

to 16 causes

WFMOutpre: BYT_Nr

to be set to 2.

Following is an example command sequence that illustrates how to transfer

waveform data from the oscilloscope to the computer.

In this case, let’s say you’d like to transfer 10,000 points from channel 1, in ASCii

format with 1 byte per point, to your computer program.

Table 2-44: Example Command Sequence for Transferring Waveform Data from Oscilloscope to Computer

Item Description

:DATa:SOUrce CH1 Sets the source waveform to be transferred to Channel 1.

:DATa:STARt 1 This, along with DATa:STOP, speciﬁes the portion of the w aveform record that will

be transferred .

:DATa:STOP 10000

:DATa:ENCdg ASCIi Sets the data format to ASCII. (This command replaces WFMOutpre:ENCdg,

WFMOutpre:BN_Fmt

and WFMOutp re:BYT_Or with a single command.)

:DATa:WIDth 1

Sets 1 byte per point (same as

WFMOutpre:BYT_Nr).

2-96 MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual

Command Groups

Table 2 -44: Example Command Sequence for Transferring Waveform Data from Oscilloscope to Computer (cont.)

Item Description

:HEADer 1 Turning on HEADer and VERBose will allow you to view the WFMOutpre?

parameters in context.

:VERBose 1

:WFMOutpre? The WFMO utpre? query provides the information needed to interpret the waveform

data point information that will be returned from the

CURVe query.

:HEADer 0

You may want to turn the header off before doing the

CURVe query, because w ith

the header on, a

CURVe query will return the CURVe command header followed by

a space and the ASCII waveform data.

:CURVe? Transfers the data points.

NOTE. Command sequence examples as well as sev eral comprehensive examples

of what the

WFMOutpre?

query might return using different data sources are

includ

ed as an appendix. (See page D-1, Waveform Transfer (WFMOutpre and

CURVe Query) Examples.)

Examp

le 1: Analog Waveform (channel 1 - 4)

Example 2: Digital Waveform (channel DO-D15)

Example 3: The Digital Collection with 4 Bytes Per Point with MagniVu Off

Example 4: The Digital Collection with 8 Bytes Per Point with MagniVu Off

Example 5: The Digital Collection with 4 Bytes Per Point with MagniVu On

Example 6: The Digital Collection with 8 Bytes Per Point with MagniVu On

ample 7: RF Frequency Domain Waveform

NOTE. Whenyoudoa

WFMOutpre?

query in an interactive session during

rogram development, it’s a good idea to ﬁrst turn on the header and verbose

features (using the

HEADer

and

VERBose

commands) in order to see the returned

values in context.

Waveform Sources. Valid waveform sources that can be transferred from the

oscilloscope (using the

DATa:SOUrce command) include:

CH1–CH4- Analog channels. When

DATa:SOUrce is set to one of these

sources, the data points represent digitizing levels. There are 25 digitizing levels

per vertical division for 1-byte data, and 6400 digitizing levels per vertical

division for 2-byte data. These data points can be transferred in signed or

unsigned integer formats.

D0 – D15 - The digital input channels (MSO/MDO4000/B models only as

well as MDO3000 and MDO4000C series models with options MDO3MSO or

MDO4000/B/C, MSO/DPO4000B and MDO3000 Series Oscilloscopes Programmer Manual 2-97