foreach ($pre_cache['raritan_inletTable'] as $index => $raritan_data) {
    for ($x = 1; $x <= $raritan_data['inletPoleCount']; $x++) {
        $tmp_index = "$index.$x";
        $new_index = "inletPoleVoltage.$tmp_index";
        $oid = '.1.3.6.1.4.1.13742.4.1.21.2.1.4.' . $tmp_index;