I am new to PHP and I am writing a PHP code to get data from a modbus device using the PHPModbus library. I need to be able to display the data every second and then write the data to a CSV file every minute.
- I have used the header('Refresh:1') to refresh the page every second.
- I get the data as raw bytes which I convert to float or int depending on the parameter.
- Then i store the data in an array 'energymeter_param' and implode the contents of the array to get a string which I want to write to the CSV file log.csv every 60 seconds.
- If you read my code you would see that I am calling the file_put_contents() function every time the value of seconds becomes 0. [ if(date('s') == 0)].
- But sometimes while refreshing the page the time skips from HH:MM:59 to HH:MM:01 directly and so i miss the data in the log file for that minute.
How do I overcome this?
<?php
// for automatically refreshing the page every one second
header('Refresh: 1');
//setting the time zone and getting the date and time
$timezone = "Asia/Calcutta";
if(function_exists('date_default_timezone_set')){
date_default_timezone_set($timezone);
}
echo date('d-m-Y'). "</br>";
echo date('H:i:s'). "</br>";
//reference to ModbusMaster.php file where the modbus php protocol is defined
require_once dirname(__FILE__) . '/phpmodbus/Phpmodbus/ModbusMaster.php';
// Create Modbus object
$modbus = new ModbusMaster("192.168.1.105", "TCP");
//Energy Meter
// FC3 = Function Code 3 to read holding registers
/*Setting device ID = 5, Starting address as 100 and
number of registers to be read as 120
*/
try {
// FC 3
$recData = $modbus->readMultipleRegisters(5, 100, 120);
}
catch (Exception $e) {
// Print error information if any
echo $modbus;
echo $e;
exit;
}
// Print status information
echo "</br>Status:</br>" . $modbus;
// Conversion
echo "<h2>EN8400</h2>
";
// Chunk the data array to set of 4 bytes
$values = array_chunk($recData, 4);
//Create an array and set first two values as date and time
$energymeter_param = array();
$energymeter_param[0] = date('Y-m-d H:i:s');
//$energymeter_param[1] = date('H:i:s');
$count = 1;
// Get float from REAL interpretation
//echo "<h3>Energy meter</h3>
";
//get each parmeter from energy meter and store in the array
foreach($values as $bytes){
/*Since load hours is unsigned long we are converting it
to unsigned long type and scaling to get correct value */
if($count == 59) {
$temp = PhpType::bytes2unsignedint($bytes);
$temp = $temp/3932160;
}
else {
$temp = PhpType::bytes2float($bytes);
//Converting Wh to Kwh
if($count == 31) {
$temp = $temp/1000;
}
}
//store the values in an array
$energymeter_param[$count] = $temp;
$count++;
}
//Store the number of energy meter parameters in a variable
$num_energymeter_param = $count;
echo "<h3>Energy meter array</h3>
";
//print array
print_r ($energymeter_param)." </br>";
//write the values to a csv file every time seconds becomes 00
if((date('s')) == 00) {
$temprow = implode(',',$energymeter_param);
$temprow.="
";
$file = 'H:\Appserv\www\Log.csv';
file_put_contents($file, $temprow, FILE_APPEND );
}