modbuslog - 2012/01/10
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modbuslog is a program designed to read from a modbus device at predefined 
intervals and store the output to file.


Compilation:
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modbuslog requires the libconfig (>1.4.8) and libmodbus (>3.0.1) libraries, 
and will not function without these libraries installed. Neither of these 
libraries are currently available (or if they are, are not of sufficient 
version) in the current Debian Stable release codenamed "Squeeze". This 
means that these dependencies must be manually fulfilled.

libmodbus: 	It should be sufficient to backport the current version of 
		libmodbus from Debian Testing codenamed "Wheezy"
		http://packages.debian.org/wheezy/i386/libmodbus5/download
		http://packages.debian.org/wheezy/i386/libmodbus-dev/download

libconfig:	An older, incompatible version of libconfig currently exists
		in Debian Squeeze (right the way up to Sid). An updated package
		has been created and will hopefully be included in the next
		Debian Stable release. In the mean time it is available here:
		http://mentors.debian.net/package/libconfig
		When it gets accepted, it will be available here:
		http://packages.debian.org/source/testing/libconfig

modbuslog uses a Makefile to ease compilation, and as such, can be compiled
by simple navigating to the directory and running "make". This will recompile
any packages that need to be compiled.

These files can then be moved to the required directories on the target system.


Required files:
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/sbin/modbuslog				executable program
/etc/modbuslog.cfg			configuration file
/var/modbuslog/				output directory where logs are stored
/var/modbuslog/interval/interval.txt	textfile storing unique interval


Configuration:
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The configuration file for modbuslog is stored in /etc/modbuslog.cfg, and is 
arranged in a hierarchical structure suitable for libconfig.

The modbus section defines the standard operating parameters for the modbus 
device, These include:
	1) device	serial port in use
	2) baud		baud rate in use
	3) data_bits	number of data bits, commonly 8.
	4) parity	parity, commonly E (even) or N (None).
	5) stop_bits	stop bits, commonly 1.
	6) retry	number of retries for each failed reading.

The reading section defines the unique reading times that the program is 
required to log at. Each entry must contain:
	1) slaveid		modbus slave id
	2) registertype		type of modbus reading
	3) startaddress		register to start reading from
	4) numregisters		number of registers to read
	5) intervalvalue	read register every x
	6) intervalunit		(m) minutes or (h) hours