Campbell Scientific Java PakBus Software Development Kit - Manual (Page 16)

Java PakBus® Software Development Kit
5.2 Managing Table Definitions
In order for data collection to be able to work, a client to the datalogger must
have an up-to-date copy of the datalogger’s table definitions so that the binary
record objects can be properly interpreted. This can be done by using the
GetTableDefsTran transaction. The result of this transaction will be in storing
a “raw table definitions” buffer in the Datalogger object which can be
accessed using the get_raw_table_defs() method. The datalogger will also
parse these raw table definitions into a collection of table definition objects
and their constituent column definition objects.
It is possible for an application to cache the raw table definitions for a station
using Datalogger.get_raw_table_defs() and to restore this using the
Datalogger.set_raw_table_defs(Packet) method. This can save the
application the considerable amount of time that it can take to download the
raw table definitions from the datalogger.
The application can access a station’s table definitions by using the
get_tables_count(), get_table(index), and get_table(name) methods.
5.3 Starting Data Collection
Data collection is handled by the DataCollectTran class. This class manages
the details of forming the command message(s) and interpreting their results in
terms of records. The DataCollectClient class declares a method that gets
called when a group of records has been collected ( on_records()) and also
when the transaction is complete ( on_complete()). The data collection
transaction is controlled by an application assigned “collect mode” object. The
following collect modes are available:
DataCollectModeAllRecords
Specifies that all of the records currently available in the table should be
collected.
DataCollectModeDateRange
Specifies that all of the records stored in the datalogger that have a time
stamp on or after a specified beginning time and earlier (but not including)
than a specified ending time should be collected.
DataCollectModeDateToNewest
Specifies that all records starting with the record at or newer than a
specified begin date up to the newest record in the table should be
collected.
DataCollectModeMostRecent
Specifies that the most recent number of records should be collected.
DataCollectModeRecordNoRange
Specifies that all records on or after the specified begin record number up
to but not including the end record number should be collected.
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