Modbus TCP and UDP library for PHP., originally from code.google.com/p/phpmodbus
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php-modbus/tutorials/Phpmodbus/Phpmodbus.pkg

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<refentry id="{@id}">
<refnamediv>
<refname>Phpmodbus user's guide</refname>
<refpurpose>Phpmodbus How-to</refpurpose>
</refnamediv>
<refsynopsisdiv>
<author>
Jan Krakora
<authorblurb>
{@link mailto:krakora.jan@googlemail.com email}
</authorblurb>
</author>
</refsynopsisdiv>
{@toc}
<refsect1 id="{@id intro}">
<title>Introduction</title>
<para>
Phpmodbus is a PHP library for the Modbus protocol. The library implements
Modbus TCP/UDP master class with subset of the most used Modbus commands.
</para>
<para>
The library implements:
<itemizedlist>
<listitem><para>FC 1: read multiple coils</para></listitem>
<listitem><para>FC 2: read input discretes</para></listitem>
<listitem><para>FC 3: read multiple registers</para></listitem>
<listitem><para>FC 6: write single register</para></listitem>
<listitem><para>FC 15: write multiple coils</para></listitem>
<listitem><para>FC 16: write multiple registers</para></listitem>
<listitem><para>FC 23: read write registers</para></listitem>
</itemizedlist>
</para>
<para>
For more about Modbus protocol see [{@link http://www.modbus.org}] or
[{@link http://en.wikipedia.org/wiki/Modbus Wiki}]
</para>
</refsect1>
<refsect1 id="{@id install}">
<title>Install</title>
<para>
At the first, it is supposed an PHP solution has been already installed on
your server (LAMP, WAMP, MSS+CGI etc.).
</para>
<para>
Copy the Phpmodbus library to your PHP project folder.
</para>
<para>
Create a PHP script and assign the library using require_once() command
<programlisting role="c">
<![CDATA[require_once dirname(__FILE__) . '/Phpmodbus/ModbusMaster.php'; ]]>
</programlisting>
</para>
<para>
To create UDP Modbus master object communicating to an modbus slave
e.g. at IP address 192.168.1.1 write
<programlisting role="c" linenumbering="numbered" startinglinenumber="2">
<![CDATA[ $modbus = new ModbusMaster("192.168.1.1", "UDP"); ]]>
</programlisting>
</para>
<para>
To create TCP Modbus master use
<programlisting role="c" linenumbering="numbered" startinglinenumber="2">
<![CDATA[ $modbus = new ModbusMaster("192.168.1.1", "TCP"); ]]>
</programlisting>
</para>
<para>
To read 5 words (10 bytes) from the device ID=0 and its memory address 12288
use try-catch method call
<programlisting role="c" linenumbering="numbered" startinglinenumber="3">
<![CDATA[try {
// Function processing
$recData = $modbus->readMultipleRegisters(0, 12288, 5);
}
catch (Exception $e) {
// Exception processing, e.g. print error information
echo $modbus;
echo $e;
exit;
}]]>
</programlisting>
</para>
<para>
To process the function byte stream, use conversion to PHP types in
</para>
<programlisting role="c" linenumbering="numbered" startinglinenumber="15">
<![CDATA[echo PhpType::bytes2string($recData); ]]>
</programlisting>
<para>
For other examples see sections bellow.
</para>
</refsect1>
<refsect1 id="{@id examples}">
<title>Examples</title>
<para>
This section presents library features and examples
</para>
<refsect2 id="{@id example_fc1}">
<title>FC1 - read mutliple coils</title>
<para>
FC1 functionality example
</para>
<para>
{@example example_fc1.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc2}">
<title>FC2 - read input discretes</title>
<para>
FC2 functionality example
</para>
<para>
{@example example_fc2.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc3}">
<title>FC3 - read mutliple registers</title>
<para>
FC3 functionality example
</para>
<para>
{@example example_fc3.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc6}">
<title>FC6 - write single register</title>
<para>
FC6 functionality example
</para>
<para>
{@example example_fc6.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc15}">
<title>FC15 - write mutliple coils</title>
<para>
FC15 functionality example
</para>
<para>
{@example example_fc15.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc16}">
<title>FC16 - write mutliple registers</title>
<para>
FC16 functionality example
</para>
<para>
{@example example_fc16.php}
</para>
</refsect2>
<refsect2 id="{@id example_fc23}">
<title>FC23 - read write registers</title>
<para>
FC23 functionality example
</para>
<para>
{@example example_fc23.php}
</para>
</refsect2>
<refsect2 id="{@id wago_example}">
<title>Dump of M-memory from WAGO 750-84x series coupler.</title>
<para>
Dump of M-memory from WAGO 750-84x series coupler.
</para>
<para>
{@example example_750841_Mmemory.php}
</para>
</refsect2>
<refsect2 id="{@id datatype}">
<title>Data conversion to PHP types.</title>
<para>
Conversion of the data bytes, received from Modbus, to a PHP type.
</para>
<para>
{@example example_datatype.php}
</para>
</refsect2>
</refsect1>
<refsect1 id="{@id back_comp}">
<title>Back compatibility</title>
<para>
This version is back compatible to the last versions. Just use
<programlisting role="c">
<![CDATA[require_once dirname(__FILE__) . '/Phpmodbus/ModbusMasterUdp.php';
$modbus = new ModbusMasterUdp("192.168.1.1");
// ... ]]>
</programlisting>
</para>
</refsect1>
</refentry>