User manual

Series 3700 System Switch/Multimeter Reference Manual Section 8: Scanning
3700S-901-01 Rev. C / July 2008 8-9
Buffer
To recall scanned readings stored in the buffer, press the REC key and turn the
navigation wheel to navigate through the buffer. See Recalling readings (on
page 7-5) for details on recalling buffer readings. When finished, make sure to
exit from buffer recall (press the EXIT key). Also see Buffer: Data Storage and
Retrieval (on page 7-1).
Changing channel and DMM attributes of an existing scan
When a scan already exists, changing channel and DMM attributes also causes
the scan to change. Once a scan list has been defined, the Series 3700 will try
to incorporate your changes into the scan. For example, changing a DMM
configuration assigned to a channel used in scanning affects the scan list. But
changing a DMM configuration on a channel not involved in scanning does not
affect the scan list. If the change impacts the ability of the scan to function
properly (such as deleting something referenced by the scan), an error message
is logged.
To see how the scan list may have changed, view the current scan list. On the
front panel, press the SCAN key and select the LIST option, using the
navigation wheel to scroll through the options. For bus operation, use the
scan.list() function. For performance reasons, it is always better to
configure all channel and DMM attributes before creating a scan. Afterward,
changes may cause the scan to take more time to modify the scan list. You can
clear an existing scan list before making any changes after making a scan list.
From the front panel, press the SCAN key and select the CLEAR option. For
bus operation, use the scan.create() function.
Some changes may cause channels to be dropped from the list when they
become paired with another channel for a 4-wire operation. These channels will
not be added back into the list during subsequent changes that free the paired
channel from a 4-wire operation. To get a recently unpaired channel back in the
list, create a new scan list or add it back into the list.
For example, a scan list is comprised of Channels 1 to 60 on a Model 3720 card
with the channels configured to measure DC volts. Changing Channels 1 to 30
to be configured for 4-wire ohms measurements causes the scan list to change.
The scan list changes to contain Channels 1 to 30 measuring 4-wire ohms, and
Channels 31 to 60 are removed because they are paired with Channels 1 to 30.
If you then change Channels 1 to 60 to be configured for measuring DC volts,
the scan list will still only contain Channels 1 to 30, but it will be measuring DC
volts. Channels 31 to 60 are not automatically added back into the list.