Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 72)

Section 4. Setting up Datalogger Networks
• Automatically Reset Changed Tables – LoggerNet will reset (delete and
recreate) any tables that have changed. Unchanged tables will not be reset.
Scheduled data collection will continue without action from the user.
• Stop Collection Until Manually Updated – Scheduled data collection will
be halted until the user manually updates the table definitions (Setup
Screen, Data Files tab, Get Table Definitions button). At that time, the
user will be prompted to Merge or Reset the table definitions.
Data Advise/One Way Data Hole Collection – A discontinuity in collected
data is referred to as a hole. Data Advise or One Way Data hole collection does
not apply to holes collected during manual data collection or scheduled data
collection since the default behavior of those collection methods will always
retrieve the records needed from the datalogger and store them in the data
cache in sequential order. However, there are settings in LoggerNet and other
data collection methods that can produce missing records in the data cache.
One Way Data and Data Advise are two collection methods that can produce
holes. These collection methods both rely on the datalogger to send records to
LoggerNet. Since the transmission of these records is unacknowledged, there is
a possibility that the data will be lost. If LoggerNet doesn’t receive a record for
any reason, a hole is created. If the Data Advise or One Way Data hole
collection check box is selected, LoggerNet will attempt to contact the
datalogger and request the missing records. Otherwise, LoggerNet will not
attempt to collect records missing from the data cache.
Please note that LoggerNet puts records from Data Advise or One Way Data
hole collection in the .dat files as they are received. If there are holes in the
data that are retrieved later, the records will not be in sequential order in the
.dat file created by LoggerNet.
Data Advise or One Way Data hole collection will not occur at a
time when doing so would force the communication link to be
dialed.
Additional Field Available in LoggerNet Admin/LoggerNet Remote
Collect Via Data Advise – When this option is enabled, an agreement is
established between the LoggerNet server and the datalogger. As part of the
Data Advise agreement, LoggerNet reports the tables that are marked for
collection and the datalogger stores that information in memory. When the
datalogger receives a communication packet of any kind, it checks for new
records in the tables marked for collection. If a new record exists, it is sent by
the datalogger to the LoggerNet server.
Data Advise is used within RF telemetry networks to increase the speed of data
collection. The RF polling process using the TD-RF (“Time-division polling”)
PROM or OS can take advantage of the Data Advise agreement to collect data
very quickly by broadcasting a communication packet to all dataloggers in the
RFBase-TD network concurrently. This broadcast packet triggers all
dataloggers to check for and send any new records at once. The records are
simultaneously stored in the individual RF remote modems (RFRemote-TD)
until retrieved through the RF polling process (initiated by the RFBase-TD).
NOTE
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