librenms-librenms/html/includes/graphs/sensor/temperature.inc.php

<?php
$scale_min = '0';
$scale_max = '60';

require 'includes/graphs/common.inc.php';

$rrd_options .= " COMMENT:'                          Min     Last   Max\\n'";

$rrd_options .= " DEF:sensor=$rrd_filename:sensor:AVERAGE";
$rrd_options .= " DEF:sensor_max=$rrd_filename:sensor:MAX";
$rrd_options .= " DEF:sensor_min=$rrd_filename:sensor:MIN";
if (is_numeric($sensor['sensor_limit'])) {
    $rrd_options .= ' CDEF:sensorwarm=sensor_max,'.$sensor['sensor_limit'].',GT,sensor,UNKN,IF';
}
$rrd_options .= ' CDEF:sensorcold=sensor_min,20,LT,sensor,UNKN,IF';
$rrd_options .= ' CDEF:sensor_diff=sensor_max,sensor_min,-';
$rrd_options .= ' AREA:sensor_min';
$rrd_options .= ' AREA:sensor_diff#c5c5c5::STACK';

if ($sensor['poller_type'] == "ipmi") {
    $rrd_options .= " LINE1.5:sensor#cc0000:'".rrdtool_escape(ipmiSensorName($device['hardware'], $sensor['sensor_descr']), 21)."'";
} else {
    $rrd_options .= " LINE1.5:sensor#cc0000:'".rrdtool_escape($sensor['sensor_descr'], 21)."'";
}

$rrd_options .= ' GPRINT:sensor_min:MIN:%4.1lfC';
$rrd_options .= ' GPRINT:sensor:LAST:%4.1lfC';
$rrd_options .= ' GPRINT:sensor_max:MAX:%4.1lfC\\l';

if (is_numeric($sensor['sensor_limit'])) {
    $rrd_options .= ' HRULE:'.$sensor['sensor_limit'].'#999999::dashes';
}

if (is_numeric($sensor['sensor_limit_low'])) {
    $rrd_options .= ' HRULE:'.$sensor['sensor_limit_low'].'#999999::dashes';
}