System information

Section 2. Protocols and Packet Types
2-19
In order to ensure the integrity of this table information, the application should
calculate a signature of the parameters contained in each table within the table
definitions. One signature should be calculated for each defined table and
should be stored and used by the application to verify that the table has not
changed when collecting data.
The signature is calculated using the parameters for each table from the Get
Table Definitions response. For each table, calculations start with the first byte
of the Table Name and end after the Field List Terminator of that table. A
description of the algorithm used to calculate the signature along with example
code is found in Appendix B. The Table Definition Signature is used to verify
that table definitions have not changed on the datalogger while data collection
operations continue.
2.3.4.3 Collect Data Transaction (MsgType 0x09 & 0x89)
The Collect Data Transaction is used to collect records from the datalogger.
Collect Data Command Body (MsgType 0x09):
Name Type Description
MsgType Byte Message type code (0x09)
TranNbr Byte Transaction number
Security Code UInt2 Security code of the datalogger
CollectMode Byte Collection mode code:
0x03: Collect from the oldest record in each
table and collect to the newest record.
0x04: Collect from “P1” to the newest record.
If the start record “P1” does not exist and is not
the next record that will be stored, collect will
start from the oldest record in each table.
0x05: Collect the most recent records where
“P1” designates how many records to collect.
0x06: Collect records that lie between “P1” and
“P2”. Include “P1” but exclude “P2”. If no
records exist between “P1” and “P2”, an empty
data response will be sent.
0x07: Collect a Time Swath where “P1” and
“P2” are the time parameters (NSec relative to
Jan 1, 1990). Get all records with time tags
greater than or equal to “P1” and less than
“P2”.
0x08: Collect a partial record when the record
size has exceeded the maximum packet size.
“P1” specifies the record number and “P2”
specifies the byte offset into the record that
was partially retrieved.
{ TableNbr UInt2 Table number
TableDefSig UInt2 Table definition signature
{ P1 } UInt4 or NSec Parameter used to specify what to collect
{ P2 } UInt4 or NSec Optional parameter used to specify what to
collect
{ FieldNbr } UInt2 Field number or an empty list to specify all
fields
(0) } UInt2 Field list terminator