Transport a PHP array to a PowerShell function

I am trying to transport a PHP array (from index.php) to a Powershell function (ps_scripts.ps1) as an argument. However, am getting an error(error below). I am using the EXEC function in PHP to pass arguments to the Powershell function.

PHP Code:

            $psPath = "powershell.exe -InputFormat none -ExecutionPolicy ByPass  -NoProfile ";
            $psDIR = "C:\\xampp\\htdocs\\";
            $psScript = "ps_scripts.ps1";
            $runScript = $psDIR. $psScript;
            $runCMD = $psPath." ".$runScript." 2>&1 "; 


            $parameter_2 = "testdata";
            $array = array("Peter"=>24, "Ben"=>"Hello");
            $encoded_data = json_encode($array);
            exec($runCMD . "example_function_name \"" . $encoded_data . "\"" . " \"" . $parameter_2 . "\"", $output, $retval);

Powershell Code - ps_scripts.ps1:

            $arguments = $args;
            function example_function_name
            {
              $sData = $arguments[0] | ConvertFrom-Json
              echo $sData;
            }

Error:

            Array ( [0] => At line:1 char:70 [1] => + ... htdocs\ps_scripts.ps1 example_function_name {Peter:24,Ben:Hell ... [2] => + ~ [3] => Missing argument in parameter list. [4] => + CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException [5] => + FullyQualifiedErrorId : MissingArgument [6] => ) 1