PHP programming skills: Implementing Modbus TCP data filtering and analysis methods

PHP Programming Tips: Implementing Modbus TCP data filtering and analysis methods

Modbus TCP is a commonly used communication protocol, which can be used to communicate with various devices and is very popular in the field of industrial control. In PHP programming, how to filter and analyze Modbus TCP data is an important skill and requirement. This article will introduce some PHP programming skills to help you implement Modbus TCP data filtering and analysis methods.

1. Establish a Modbus TCP connection

In PHP, we can use the "phpmodbus" library to establish a connection with a Modbus TCP device. First, we need to install the library. Run the following command to install:

composer require modbus/tcp-php

After the installation is complete, we can use the library. The following is a code example to establish a Modbus TCP connection:

<?php

require __DIR__.'/vendor/autoload.php';

use ModbusTcpClientNetworkBinaryStreamConnection;

$ip = '192.168.1.100';
$port = 502;

$connection = new BinaryStreamConnection($ip, $port);
$connection->connect();

// 在这里可以进行Modbus TCP通信

$connection->close();

2. Send Modbus TCP request

After establishing a connection with the device, we can use the "phpmodbus" library to send Modbus TCP requests. The following is a code example that sends a Modbus TCP request to read holding registers:

...

use ModbusTcpClientRequestReadHoldingRegistersRequest;
use ModbusTcpClientUtilsTypes;

$request = new ReadHoldingRegistersRequest(0, 10);
$response = $connection->sendRequest($request);

if ($response->isOk()) {
    $data = Types::parseByteArray($response->getData());
    print_r($data);
} else {
    echo '请求失败：' . $response->getErrorMessage();
}

...

The above code sends a request to read 10 holding registers starting from address 0, and parses the resulting data into an array. Print.

3. Data screening and analysis

In actual projects, all data are usually not processed directly, but screened and analyzed according to needs. For example, if we only want to get the data with a value greater than 100 in the holding register, we can use the following code to filter and analyze:

...

if ($response->isOk()) {
    $data = Types::parseByteArray($response->getData());

    $filteredData = array_filter($data, function($value) {
        return $value > 100;
    });

    print_r($filteredData);
} else {
    echo '请求失败：' . $response->getErrorMessage();
}

...

The above code uses the array_filter function to filter the data. Keep data with values ​​greater than 100 and print them.

4. Summary

Through the above PHP programming skills, we can easily implement the screening and analysis of Modbus TCP data. First, we establish a connection to the Modbus TCP device; then, we send the Modbus TCP request and process the data in it. Finally, we also show how to filter and analyze the data.

I hope this article can help you flexibly apply the screening and analysis methods of Modbus TCP data in PHP programming. Happy coding!

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