Campbell Scientific ST-21 Argos Satellite Transmitter - Manual (Page 10)

ST-21 Argos Satellite Transmitter
2.2 ArgosData
ArgosData (ResultCode, ST21Buffer, DataTable, NumRecords, DataFormat)
2.2.1 General Description
The ArgosData instruction is used to load data to one of the 7 available data
buffers. The data buffers are numbered 0 through 7, with number 7 being
reserved for the ST-21 internal temperature. When ArgosData is executed, any
data already in the associated buffer is erased before new data is loaded. If the
Argos ID number associated with the buffer is a 20 bit ID number, up to 32
bytes of data can be loaded. If the associated ID number is a 28 bit ID, then
only 31 bytes can be loaded. Extra bytes are discarded. The ArgosData
instruction does not enable data transmission. To enable data transmission, the
ArgosDataRepeat, or ArgosTransmit instruction must be used.
2.2.2 ResultCode
The Result Code is a numeric variable used to store the result of the ArgosData
instruction. If the result code is true (-1), ArgosData executed successfully.
2.2.3 ST21Buffer
The ST21Buffer is the number of the buffer where data should be loaded.
Valid buffer numbers are 0 through 6.
2.2.4 DataTable
DataTable is the name of the data table where data records will be read from.
2.2.5 NumRecords
NumRecords is the number of data records that will be copied from the data
table to the Argos PTT. Care should be taken to make sure the total amount of
data does not exceed what the buffer can hold, 32 bytes for a 20 bit ID number
and 31 bytes for a 28 bit ID number. See DataFormat (Section 2.2.6) for
details on regarding memory usage.
2.2.6 DataFormat
There are two data formats. Enter “FP2” to use the Campbell Scientific two
byte, floating decimal point format. To use FP2, the data table (Section 2.2.4)
must store data as type FP2. Each data value will use two bytes of memory.
Enter “nnn.nnn.nnn…” to use the integer format, where nnn is an integer that
specifies the total number of bits to be used for each data value. As an
example: “5,8,16,8,3” would use 5 bytes or 40 bits for five data values. The
first data value would have 5 bits of resolution, then 8 for the next, then 16 for
the third and so forth. With the integer format, data must be stored in the data
table as type Long.
When using integer format with bits/data point designator, each data point in
the data record needs to be accounted for in the DataFormat field, or the
datalogger will assume 2 bytes (16 bits) for each unaccounted for data point.
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