Understanding Scanning Modes - HP E1313A Manual

Understanding Scanning Modes

Chapter 4
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The HP E1413 is a 64-Channel Scanning Analog-to-Digital Converter.
The sequence of channels to scan are specified in a scan list. Scanning is
the only way the module makes measurements. A scan list can contain as
few as two channels (three if Sample and Hold SCP installed) and as many
as 1,024 channels.
Once the module has been initiated and triggered, it " executes" the current
scan list and stores the resultant readings in the 64-channel Current Value
Table (CVT) and in the 65,023 reading FIFO buffer (FIFO). Different
sequences of channels can be specified in each of four scan lists. Any of the
four scan lists that have been defined (channels specified) can be selected as
the current scan list.
After being initiated, the module executes the current scan list once for each
trigger event. There are several choices for the trigger source:
Several software trigger methods.
–
The VXIbus TTLTRG lines.
–
The external trigger input.
–
An on-board programmable trigger timer.
–
Continuously triggered (
–
The module provides three main modes of scanning:
•
The "Default Mode" is set when
and the
TRIGger:COUNt
also set this mode. The sequence of events for this mode is shown in
Figure 4-4 A. Note that starting at the trigger idle state, you must
execute an INITiate
shows that the current scan list (as set by
becomes effective after the
•
The "Counted Mode" is set when
and the
TRIGger:COUNt
INITiate command will allow as many scans as
specifies. Note that
INFinity . The sequence of events for this mode is shown in
Figure 4-4 B. The sequence shows that the current scan list is only set
at the start of the counted scan. This means that the current scan list can
not be changed while the module is scanning. However, by specifying
LISTL as the current scan list before
sequence of scan lists specified in
Understanding the HP E1313/E1413
TRIGger:SOURce IMMediate
INITiate:CONTinuous
is set to . Power-on and the
1
command to begin each scan. The sequence also
ROUTe:SCAN <
INITiate command.
INITiate:CONTinuous
is set greater than . In this mode, a single
1
TRIGger:COUNt can be from
INITiate:CONTinuous ON
LISTL will be executed.
).
is set to ,
OFF
command
*RST
scan_list > )
is set to ,
OFF
TRIGger:COUNt
2 to 32768 or
, the
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