Executing PowerShell Script from Server Using PHP

I have a PowerShell script hosted on a server. I am calling PowerShell script from Php as below:

<?php
header('Content-Type: text/plain');
$csv = file_get_contents('http://domaincom/wp-content/uploads/csv-samples.csv');
echo $csv;

shell_exec('pwsh -File http://domaincom/wp-content/uploads/pscript.ps1');

$psPath = "powershell.exe";
$psDIR = "http://domaincom/wp-content/uploads/";
$psScript = "pscript.ps1";
$runScript = $psDIR. $psScript;
$runCMD = $psPath." ".$runScript." 2>&1"; 

echo "\$psPath  $psPath <br>";
echo "\$psDIR  $psDIR <br>";
echo "\$psScript  $psScript <br>";
echo "\$runScript  $runScript <br>";
echo "\$runCMD   $runCMD  <br>";

exec( $runCMD,$out,$ret);

echo "<pre>";
print_r($out);
print_r($ret);
echo "</pre>";
?>

Script executes and I can see csv-samples.csv results in browser, but the powershell script doesn't execute. I get below message in browser:

Site,URL,Category
Sitepoint,http://www.sitepoint.com/,Web development
Html.it,http://www.html.it/,Web development
Wamboo,http://www.wamboo.it/,Web development$psPath  powershell.exe <br>$psDIR  http://domaincom/wp- 
content/uploads/ <br>$psScript  pscript.ps1 <br>$runScript  http://domaincom/wp- 
content/uploads/pscript.ps1 <br>$runCMD   powershell.exe http://domaincom/wp- 
content/uploads/pscript.ps1 2>&1  <br><pre>Array
(
    [0] => sh: 1: powershell.exe: not found
)
127</pre>

Your help is very much appreciated.

Thank You.