Overview

fancmodbus is a wrapper library for the libmodbus library, which can be found under http://libmodbus.org/

The modbus protocol is an industry standard protocol for controlling switchboards over serial lines or TCP. The standard is maintained at http://www.modbus.org/

Location of Packages

SVN: svn+ssh://fancylibs@svn.clazzes.org/fancylibs/trunk/fancymodbus

repositories:

• http://deb.clazzes.org/debian/sources.list.d/wheezy/wheezy-fancylibs-3.list
• http://deb.clazzes.org/debian/sources.list.d/jessie/jessie-fancylibs-3.list

Installation

Tools

These packages are standalone programs to deal with the modbus protocol:

apt-get install fancymodbus-tool fancymodbus-simulator

If you only need the library, install the following packages:

apt-get install libfancymodbus1 libfancymodbus

Debug symbols

All packages have a counterpart containing debug symbols for gdb:

fancymodbus-tool-dbg fancymodbus-simulator-dbg libfancymodbus-dbg

Using the command line tool

Read Output Bits

The fancymodbus-tool client lets you read and write DO output bits/coils using the following commands:

fancymodbus-client writeDO 127.0.0.1:1502 1 0x105 1 0 1 0 1
fancymodbus-client readDO 127.0.0.1:1502 1 0x105 5

These example reads and writes 5 output bits starting with address 0x105.

If you do not want to conenct to the locally listening fancymodbus-simulator, you need to specify the IP of a real device like 192.168.127.254:502.

Configuring fancymodbus-simulator

Edit /etc/fancymodbus/simulator.conf and change the listen port or the number of registers.

For the most part you should not need to edit the default configuration, which listens to 127.0.0.1:1502 and provides for 512 registers of each kind.

Activate the daemon in /etc/default/fancymodbus-simulator

# set to yes if you want automatic starting
FANCYMODBUS_SIMULATOR_START="yes"

Start the daemon

/etc/init.d/fancymodbus-simulator start

The daemon logs it's diagnostics to /var/log/syslog