Operating Manual CHM 8k
R1.7 / 01-2020
Communication via RS485 & Ethernet
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[recipient]
ftp://afd:[email protected]//home/chm_data/%h/%tY/%tm
[options]
priority 9
create target dir
time */15 * * * *
lock DOT
age-limit 3600
exec -d bzip2 %s
Every 15 minutes, bzip-compressed files are transferred to the ftp server in a directory specified by
/home/chm_data/hostname/year/m
onth. Hostname “%h” is the device name, e.g. CHM198001, year
“%tY” and month “%tm” are the time settings specified by the device.
A double-slash // after the IP address indicates that the path starts in the source directory; a single slash
/ indicates that the path starts from the ftp-home directory.
An ftp path in the Windows directory may look like this:
ftp://afd:[email protected]/%h/%tY/%tm.
The file is stored in the subdirectory /%h/%tY/%tm of the main directory on the ftp server.
The command “time * * * * *” sends a 5-minute NetCDF file immediately after it is created
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 8.3 Data query RS485 can be requested. 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 port "LanPort" 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 sent and then the connection from the CHM will be
stopped.
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 ncrcat.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.