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Collection of bash-Scripts to communicate with L2P devices from G. Lufft Mess- und Regeltechnik GmbH
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# lp2 script collection
# (c) 2012, Ondics GmbH | |

Update 2013-12-09: Some files were deleted. Please contact us at 
                   Thanks for your interest.

1. description
2. installation
3. device detection in the local network
4. the scripts
5. examples of full command chains
6. licensing
7. integration into nagios network management software

1. description
the "l2p script collection" provides some useful
scripts to communicate with l2p devices.
l2p is the "lufft logger protocol" developed by
G. Lufft Mess- und Regeltechnik GmbH in Germany
(, a producer of climatological
precision measuring equipment.

scripts provided:
l2p-crc16                       calculating crc16-checksums
l2p-datatype-convert.gawk       converting datatypes to decimal values
l2p-examples                    some example hex strings for dry testing (without a device)
l2p-frame                       generating frames for requests
l2p-result                      analyzing results from requests
test                            test cases for testing purposes

2. installation

prerequisites are:
- gawk has to be installed
- scripts are written in bash
- nc or netcat is used for connecting the l2p-device
- ngrep to detect l2p devices in the local network

3. device detection in the local network
e.g. for opus 20 thip device:
first initalize device with button on the backside (lan init).
then detect udp broadcast with:
> ngrep '' 'udp and port 52010'
attention: ngrep requires root to run, so as user 
> sudo ngrep '' 'udp and port 52010'
will work better

the result looks like:
# U ->

the ip address of this device is

alternatively the lufft smartgraph3 software can be used
(for free download check

4. the scripts

bash-skript to calculate CRC-16 CCITT checksum.
output is written in ascii to stdout by default.
input comes as script argument.
usage example:
> ./l2p-crc16 "30 31 32 33 34 35 36 37"

bash-skript to build a full L2P-Frame from a given l2p command,
output is written in ascii to stdout by default.
e.g. "23 10" to get the device status. 
usage example for request "23 10":
> ./l2p-frame "23 10"

bash-script to analyze result from device given in l2p format.
output is written in ascii to stdout by default.
input comes from stdin by default.
usage example for request "31 10 16":
>  cat ./l2p-examples/result_31_10_16_kanaele.hex | ./l2p-result --ascii -v
shows all channels available (--ascii is for ascii input)

gawk-script to convert hex-values to ascii strings with
their decimal equivalents using the ieee 754 procedure.
all l2p data types are supported in big or little endian.
float conversion uses ieee 754 spec.
usage example: echo "BE FLOAT 43478a3d"| gawk -f l2p-datatype-convert.gawk
gives 199.539993 as result

files in ./l2p-examples:
the example files *.hex are ascii hex strings
the example files *.dat are binary hex strings
they can be used to play with the scripts without using a device

bash-script with several test cases to demonstrate script usage
usage example:
>  ./test 4
attention: use ./ as path because of unix test-command!

5. examples of full command chains
to retrieve a channel list, use:
> echo "31 10 16"| ./l2p-frame -x | nc -i 2 -q 1 52015 | ./l2p-result
gives a list with all channels available.

to retrieve one channel (e.g. current air pressure, channel 300=0x012c), use:
> echo "23 10 2c 01"| ./l2p-frame -x | nc -i 2 -q 1 52015 | ./l2p-result
gives 969.470032 as result

6. licensing
# The Scripts are dual licensed under commercial and GPL Version 3
# licenses (except l2p-crc16. For commercial license conditions please
# contact us.
# As free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.

7. integration into nagios network management software
there is an nagios plugin available to integrate any l2p device
in your network management environment.
see on github project ...

hav fun!
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