Appendix D _________________________________________________ RVP900 Developer's Notes
VAISALA______________________________________________________________________ 419
D.13.2 Attach/Detach Details
Use rvptsAttach() to attach and rvptsDetach() to release the connection.
Always attach to unit RVPTS_UNIT_MAIN; the others are for internal
RVP use. You must also specify the client type you are. Readers are
generic, but for writers, there are several choices because we need to
switch sources, and we need to know who the sources are.
See the example program rda/rdasubs/rvpts_example.c. Other programs
using the Timeseries API are:
- ts/export/tsexport.C
- ts/export/tsimport.C
- ts/switch/tsswitchMainWin.C
- ts/exec/TsArchExec.C
- ts/exec/tsclientshell.C
- ts/archive/tsarchAS.C
D.13.3 Extracting Pulses via Sequence
Numbers
Because there is a ring buffer filled with time series, the first thing a reader
should do is get the most recent pulse, and start reading after that. We do
that with the function rvptsCurrentSeqNum(). Take a look at the source
code to tsexport.C to see how this is done. To get data starting at a specific
sequence number, use rvptsGetPulses(). If there are none available, then
we should sleep to wait for some more.
If the RVP is reconfigured in some way, this causes a change in the
"acquisition mode". An example might be that the PRF, pulse width, or
transmit polarization has changed. All data read from a single call to
rvptsGetPulses() will be for the same acquisition mode.
D.13.4 Using Memory Bandwidth
Effectively
It will be a waste of effort to read each pulse of data individually. So a
smart reader sleeps until at least, say, 10 pulses have arrived before reading
them. To support this, there are function calls to find out how many pulses
are available after a give sequence number, and how old a given pulse is.
Look at tsexport.C to see how to use this.
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