Phpmodbus user's guide
Phpmodbus How-to
Jan Krakora
{@link mailto:krakora.jan@googlemail.com email}
{@toc}
Introduction
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.
The library implements:
FC 1: read multiple coils
FC 3: read multiple registers
FC 15: write multiple coils
FC 16: write multiple registers
FC 23: read write registers
For more about Modbus protocol see [{@link http://www.modbus.org}] or
[{@link http://en.wikipedia.org/wiki/Modbus Wiki}]
Developed with support of ![]()
{@link http://www.wago.com}.
Install
At the first, it is supposed an PHP solution has been already installed on
your server (LAMP, WAMP, MSS+CGI etc.).
Copy the Phpmodbus library to your PHP project folder.
Create a PHP script and assign the library using require_once() command
To create UDP Modbus master object communicating to an modbus slave
e.g. at IP address 192.168.1.1 write
To create TCP Modbus master use
To read 5 words (10 bytes) from the device ID=0 and its memory address 12288
use try-catch method call
readMultipleRegisters(0, 12288, 5);
}
catch (Exception $e) {
// Exception processing, e.g. print error information
echo $modbus;
echo $e;
exit;
}]]>
To process the function byte stream, use conversion to PHP types in
For other examples see sections bellow.
Examples
This section presents library features and examples
FC1 - read mutliple coils
FC1 functionality example
{@example example_fc1.php}
FC3 - read mutliple registers
FC3 functionality example
{@example example_fc3.php}
FC15 - write mutliple coils
FC15 functionality example
{@example example_fc15.php}
FC16 - write mutliple registers
FC16 functionality example
{@example example_fc16.php}
FC23 - read write registers
FC23 functionality example
{@example example_fc23.php}
Dump of M-memory from WAGO 750-84x series coupler.
Dump of M-memory from WAGO 750-84x series coupler.
{@example example_750841_Mmemory.php}
Data conversion to PHP types.
Conversion of the data bytes, received from Modbus, to a PHP type.
{@example example_datatype.php}
Back compatibility
This version is back compatible to the last versions. Just use