
5-1
IM DL850E-01EN
5 Waveform Acquisition
Based on the data that has been stored in the acquisition memory, the DL850E/DL850EV performs various
operations, such as displaying waveforms on the screen, computing, measuring cursors, and automatically
measuring waveform parameters.
This chapter explains how to set the number of data points to store in the acquisition memory (the record length),
how to enable or disable the sample data averaging feature, and so on.
Record Length (Record Length)
Record length
refers to the number of data points that are stored to the acquisition memory for each channel.
Display record length
refers to the data points from the data stored in the acquisition memory that are displayed
on the screen. Normally, the acquisition-memory record length and display record length are the same, but the
time axis setting may cause them to differ. When you change the time axis setting, the sample rate and record
length also change.
On the standard model of the DL850E/DL850EV, you can set the record length to a value between 1 kpoint and
250 Mpoint. On models with the /M2 option, you can set the length to up to 2 Gpoint. On models with the /HD0
option or /HD1 option and the /M2 option, when you enable hard disk recording, you can set the record length to
up to 50 Gpoint. For details about the record lengths that can be set, see appendix 2 in the
getting started guide
,
IM DL850E-03EN.
Use a long time axis setting when you want to observe a phenomenon over a long period of time. When you
want to observe a phenomenon at a high time resolution, set a long record length, and raise the sample rate.
When the record length is long, computation and measurement processing take longer than when the record
length is short.
The amounts of time for which you can record data to the acquisition memory when the record length is 2 Gpoint
are listed below.
Sample Rate
In Seconds
In Minutes
In Hours
In Days
100 MS/s
20
0.33
0.0056
0.00023
10 MS/s
200
3.33
0.056
0.0023
1 MS/s
1800
30
0.50
0.021
100 kS/s
18000
300
5.0
0.21
10 kS/s
180000
3000
50
2.1
1 kS/s
1728000
28800
480
20
500 S/s
2593000
43217
720
30
The following limitations on waveform acquisition conditions and the number of waveforms that can be stored
in the acquisition memory (the number of history waveforms) apply depending on the set record length.
Notes about Setting the Record Length
• Increasing the record length automatically limits the number of channels that can be used. When some
channels are unavailable, the number of channels that can be used appears in the record length setup
menu.
• When the acquisition mode is set to Average, the maximum record length is 5 Mpoint on standard models,
10 Mpoint on models with the /M1 option, and 25 Mpoint on models with the /M2 option.
• When the dual capture feature is being used, the maximum record length is 100 Mpoint on standard
models, 500 Mpoint on models with the /M1 option, and 1 Gpoint on models with the /M2 option.
• The maximum record length during hard disk recording is 50 Gpoint (one channel).
• When the trigger mode is Auto, Auto Level, Normal, or N Single and the display is not in roll mode, you can
select only a record length that is less than 5 Mpoint on standard models, 10 Mpoint on models with the
/M1 option, or 25 Mpoint on models with the /M2 option.
• On the DL850E/DL850EV, record lengths are expressed in units of points. There are some products, such
as the DL750, for which record lengths are expressed in units of words.