Skip to content
master
Switch branches/tags
Code

mbpoll

Copyright © 2015-2019 epsilonRT, All rights reserved.

Abstract

mbpoll is a command line utility to communicate with ModBus slave (RTU or TCP).
It uses libmodbus.
This is a multiplatform project, the compilation was tested on GNU Linux x86 and x86_64, Microsoft Windows 7 x86 and GNU Linux ARM 6 (Raspbian).
Although the syntax of these options is very close modpoll proconX program, it is a completely independent project.

mbpoll can:

  • read discrete inputs
  • read and write binary outputs (coil)
  • read input registers
  • read and write output registers (holding register)

The reading and writing registers may be in decimal, hexadecimal or floating single precision.

Quickstart guide

The fastest and safest way to install mbpoll is to use the APT repository from piduino.org, so you should do the following :

wget -O- http://www.piduino.org/piduino-key.asc | sudo apt-key add -
sudo add-apt-repository 'deb http://apt.piduino.org stretch piduino'
sudo apt update
sudo apt install mbpoll

This repository provides mbpoll and libmodbus (version 3.1.4) packages for i386, amd64, armhf and arm64 architectures. In the above commands, the repository is a Debian Stretch distribution, but you can also choose Ubuntu Trusty, Xenial or Bionic by replacing stretch with trusty, xenial or bionic.
It may be necessary to install the software-properties-common package for add-apt-repository.

For Raspbian you have to do a little different :

wget -O- http://www.piduino.org/piduino-key.asc | sudo apt-key add -
echo 'deb http://raspbian.piduino.org stretch piduino' | sudo tee /etc/apt/sources.list.d/piduino.list
sudo apt update
sudo apt install mbpoll

The Raspbian repository provides Piduino packages for armhf architecture for Stretch only.

Build from source

For example, for a debian system:

  • Install libmodbus (Version >= 3.1.4) :

      $ sudo apt-get install build-essential libtool git-core autoconf automake
      $ git clone https://github.com/stephane/libmodbus.git
      $ cd libmodbus
      $ ./autogen.sh
      $ ./configure
      $ make
      $ sudo make install
    

You can also install it with apt if the version of libmodbus is greater than or equal to 3.1.4. For example to query a debian system:

$ apt-cache show libmodbus-dev
  • Install piduino only if you want to manage the RS485 with a GPIO signal:

      $ sudo apt-get install cmake libcppdb-dev pkg-config libsqlite3-dev sqlite3 libudev-dev
      $ git clone https://github.com/epsilonrt/piduino.git
      $ cd piduino 
      $ git checkout dev
      $ mkdir build
      $ cd build
      $ cmake ..
      $ make
      $ sudo make install
    
  • Generate Makefile with cmake:

      $ sudo apt-get install cmake pkg-config
      $ cd mbpoll
      $ mkdir build
      $ cd build
      $ cmake ..
    
  • Compile and install mbpoll:

      $ make
      $ sudo make install
      $ sudo ldconfig
    

If you prefer, you can in the place of direct compilation create a package and install it:

    $ make package
    $ sudo dpkg -i * .deb

That's all !

Examples

The following command is used to read the input registers 1 and 2 of the slave at address 33 connected through RTU /dev/ttyUSB2 (38400 Bd)


    $ mbpoll -a 33 -b 38400 -t 3 -r 1 -c 2 /dev/ttyUSB2
    
    mbpoll 0.1-10 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>

    Protocol configuration: Modbus RTU
    Slave configuration...: address = [33]
                            start reference = 1, count = 2
    Communication.........: /dev/ttyUSB2, 38400-8E1 
                            t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, input register table

    -- Polling slave 33... Ctrl-C to stop)
    [1]: 	9997
    [2]: 	10034
    -- Polling slave 33... Ctrl-C to stop)
    [1]: 	10007
    [2]: 	10034
    -- Polling slave 33... Ctrl-C to stop)
    [1]: 	10007
    [2]: 	10034
    -- Polling slave 33... Ctrl-C to stop)
    [1]: 	10007
    [2]: 	10034
    ^C--- /dev/ttyUSB2 poll statistics ---
    4 frames transmitted, 4 received, 0 errors, 0.0% frame loss

    everything was closed.
    Have a nice day !

Help

A complete help is available with the -h option:

usage : mbpoll [ options ] device|host [ writevalues... ] [ options ]

ModBus Master Simulator. It allows to read and write in ModBus slave registers
                         connected by serial (RTU only) or TCP.

Arguments :
  device        Serial port when using ModBus RTU protocol
                  COM1, COM2 ...              on Windows
                  /dev/ttyS0, /dev/ttyS1 ...  on Linux
                  /dev/ser1, /dev/ser2 ...    on QNX
  host          Host name or dotted IP address when using ModBus/TCP protocol
  writevalues   List of values to be written.
                If none specified (default) mbpoll reads data.
                If negative numbers are provided, it will precede the list of
                data to be written by two dashes ('--'). for example :
                mbpoll -t4:int /dev/ttyUSB0 -- 123 -1568 8974 -12
General options : 
  -m #          mode (rtu or tcp, TCP is default)
  -a #          Slave address (1-255 for rtu, 0-255 for tcp, 1 is default)
                for reading, it is possible to give an address list
                separated by commas or colons, for example :
                -a 32,33,34,36:40 read [32,33,34,36,37,38,39,40]
  -r #          Start reference (1 is default)
                for reading, it is possible to give an address list
                separated by commas or colons
  -c #          Number of values to read (1-125, 1 is default)
  -u            Read the description of the type, the current status, and other
                information specific to a remote device (RTU only)
  -t 0          Discrete output (coil) data type (binary 0 or 1)
  -t 1          Discrete input data type (binary 0 or 1)
  -t 3          16-bit input register data type
  -t 3:int16    16-bit input register data type with signed int display
  -t 3:hex      16-bit input register data type with hex display
  -t 3:string   16-bit input register data type with string (char) display
  -t 3:int      32-bit integer data type in input register table
  -t 3:float    32-bit float data type in input register table
  -t 4          16-bit output (holding) register data type (default)
  -t 4:int16    16-bit output (holding) register data type with signed int display
  -t 4:hex      16-bit output (holding) register data type with hex display
  -t 4:string   16-bit output (holding) register data type with string (char) display
  -t 4:int      32-bit integer data type in output (holding) register table
  -t 4:float    32-bit float data type in output (holding) register table
  -0            First reference is 0 (PDU addressing) instead 1
  -B            Big endian word order for 32-bit integer and float
  -1            Poll only once only, otherwise every poll rate interval
  -l #          Poll rate in ms, ( > 100, 1000 is default)
  -o #          Time-out in seconds (0.01 - 10.00, 1.00 s is default)
  -q            Quiet mode.  Minimum output only
Options for ModBus / TCP : 
  -p #          TCP port number (502 is default)
Options for ModBus RTU : 
  -b #          Baudrate (1200-921600, 19200 is default)
  -d #          Databits (7 or 8, 8 for RTU)
  -s #          Stopbits (1 or 2, 1 is default)
  -P #          Parity (none, even, odd, even is default)
  -R [#]        RS-485 mode (/RTS on (0) after sending)
                 Optional parameter for the GPIO RTS pin number
  -F [#]        RS-485 mode (/RTS on (0) when sending)
                 Optional parameter for the GPIO RTS pin number

  -h            Print this help summary page
  -V            Print version and exit
  -v            Verbose mode.  Causes mbpoll to print debugging messages about
                its progress.  This is helpful in debugging connection...

Copyright © 2015-2019 Pascal JEAN, All rights reserved.

mbpoll is 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, either version 3 of the License, or (at your option) any later version.

mbpoll is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with mbpoll. If not, see http://www.gnu.org/licenses/.