Agilent Technologies 34970A, User Manual, Page: 92 / 356

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Chapter 4 Features and Functions
Scanning
• While a scan is running, you can perform some low-level control
operations on modules that do not contain channels in the scan list.
For example, you can open or close channels or issue a Card Reset on
switching modules that do not contain channels in the scan list.
However, you cannot change any parameters that affect the scan
(channel configuration, scan interval, scaling values, alarm limits,
Card Reset, etc.) while a scan is running.
• When you add a digital read (multifunction module) to a scan list,
that port is dedicated to the scan. The instrument issues a Card Reset
to make that port an input port (the other port is not affected).
• While a scan is running, you can perform low-level control operations
on any channels on the multifunction module that are not in the scan.
For example, you can output a DAC voltage or write to a digital port
(even if the totalizer is part of the scan list). However, you cannot
change any parameters that affect the scan (channel configuration,
scan interval, Card Reset, etc.) while a scan is running.
• If a scan includes a read of the totalizer, multifunction module, the
count is reset each time it is read during the scan only when the
totalizer reset mode is enabled (
TOTalize:TYPE RRESet
command
or the Advanced menu for the totalizer).
• If you install a module while a scan is running, the instrument will
cycle power and resume scanning. If you remove a module while a
scan is running, the instrument will cycle power, and it will not
resume scanning when the reboot completes. If you are logging to a
USB drive, the instrument will not log any scans that occur between
the removal of the module and the reboot of the instrument.
• You can use either the internal DMM or an external DMM to make
measurements of your configured channels. However, the instrument
allows only one scan list at a time; you cannot scan some channels
using the internal DMM and others using an external DMM.
Readings are stored in 34970A/34972A memory
only when the
internal DMM is used.
• If the internal DMM is installed and enabled, the instrument will
automatically use it for scanning. For externally-controlled scans, you
must either remove the internal DMM from the 34970A/34972A or
disable it (see
“Internal DMM Disable” on page 145 ).
34970A Refresh UG.book Page 92 Wednesday, February 17, 2010 12:34 PM