Vaisala RVP900 - Attach and Detach Details; Extracting Pulses with Sequence Numbers; Using Memory Bandwidth Effectively

The API is most valuable in providing random access to the recent buered (I,Q) data and
can buer a couple of seconds of data within the TimeSeries API. This means that
programs using the API only need to check the data every 50 to 100 msec without the risk
of losing any data. This has only a minimal load on the CPU.
D.3.2 Attach and Detach Details
Use rvptsAttach() to attach and rvptsRelease() to release the connection.
Always attach to unit RVPTS_UNIT_MAIN. The others are for internal RVP use. You must
also specify your client type. 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.
For commands, see program /rda/tsapi_lib/. The same directory includes the
rvpts_example.c example.
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.3.3
Extracting Pulses with Sequence Numbers
Because there is a ring buer filled with time series, a reader should first get the most recent
pulse, and start reading after that. We do that with the function rvptsCurrentSeqNum().
Check 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 RVP is reconfigured, 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() is for the same acquisition mode.
D.3.4
Using Memory Bandwidth Eectively
Reading each pulse of data individually is inecient. Instead, a smart reader sleeps until, for
example, 10 pulses have arrived before reading them.
To support this, function calls find out how many pulses are available after a give sequence
number, and how old a given pulse is.
For more information, see tsexport.C.
RVP900 User Guide M211322EN-J
392