Operating Manual CHM 15k
R13 / 07-2019
Communication via RS485 & Ethernet
55
8.9 Telegram via Ethernet
In addition to the RS485 interface, it is also possible to receive data telegrams via the Ethernet interface.
There are two different transmission modes. The telegrams can be interrogated individually (polling
mode) or sent automatically by the Ceilometer.
For the configuration of the behavior of the telegram output via Ethernet the parameter „LanPort“,
„LanTelegramNumber“ and „LanTransferMode“ are available. These parameters can be set via RS485
or in the register “Config Network” of the web interface, refer to Table 4.
All user data telegrams described in section
can be called up. The raw data
telegram is still uuencoded as in RS485 transmission mode and must be uudecoded before it can be
read.
The Ceilometer (server) waits on the "LanPort" port until an external (client) connection request is
received. Only then it can send telegrams to the client. Such a request can be executed for example with
ncat or telnet. A request of a client to a CHM with the IP 192.168.100.101 and a LanPort of 11000 can
look like this:
ncat 192.168.100.101 11000
or
telnet 192.168.100.101 11000
On Windows operating systems, binary net tool files can be downloaded and installed from the server
https://nmap.org/download.html
. This website also provides binary and source codes for other operating
systems.
After a connection request from the client, in the
polling mode
just a single telegram (in the
“LanTelegramNumber” specified format) will be send and then the connection from the CHM finished.
In the
automatic transfer mode
, the CHM is sending continuously (in the logging interval) telegrams to
all connected clients.
8.10 NetCDF file tools
Several tools are available for processing, modifying, or merging NetCDF files. In particular, when used
in AFD mode the ncrca.exe program is very powerful for merging files, in order to create 24-hour files
from individual 5-minute files.
The same command can also be used to merge individual NetCDF files from raw data telegrams into day
files.
ncrca is part of the nco tool set and can be downloaded from the following website:
For users of the Windows operating system:
The direct application of the command ncrca.exe in the Windows command line is restricted by the use
of wildcards and the total length of the command line. We recommend using git-bash, for example, to
circumvent this problem.
Example:
The following command line allows the merging of all NetCDF files that are located in the data directory
of device CHM123456 for April 6, 2015. The output file of the example is out.nc.
ncrca.exe -Y ncrcat -h data/20150406_Berlin_CHM123456*.nc out.nc
Summary of Contents for CHM 15k
Page 1: ...General Information 1 Titelseite...
Page 73: ...Index of Tables 73...
