rrdtool problem

[baggins]

Hi,

For those who might be interested to get these multi-valued graphs in their visualization, this is what I ended up doing:

-mark the objects to be used as 'export'.
-the second step involves another server that runs 24x7, otherwise the graphs will be incomplete... I used a powerful machine that I use for backups, Logitech Media Server, zoneminder, etc. I believe that a simple raspberry should do the trick also.
-create rrd archive (see original post).
-schedule a script that runs every x minutes. My script fetches the data, updates the rrd, creates the graph and moves it to the DocumentRoot of the webserver.

This is the script (note that this is quite a basic script with no error checking etc...

Code:

require('socket.http')
socket.http.TIMEOUT = 15

-- get data
local LM_data = socket.http.request('http://remote:remote@<ip_of_LM>/scada-remote?m=xml&r=objects')

if not LM_data then
 log('Data cannot be fetched.')
 return
end
for i in string.gmatch(LM_data, '<object.-</object>') do
 if i ~= nil then
     address =  i:match([[<address>(.-)</address>]])
     data =  i:match([[<data>(.-)</data>]])
     if address == '4/1/11' then
         T_intake = data
     end
     if address == '4/1/12' then
         T_supply = data
     end
     if address == '4/1/14' then
         T_discharge = data
     end
     if address == '4/1/13' then
         T_exhaust = data
     end
 end
end

-- update rrd
rrdupdate = "rrdtool update <path_to>/ventilatie.rrd N:" ..T_intake ..":" ..T_supply ..":" ..T_discharge ..":" ..T_exhaust

result = os.execute(rrdupdate)

--create graph
rrdgraph = "rrdtool graph <path_to>/ventilatie.png -a PNG --title='Ventilatie °C' --slope-mode " ..
" DEF:T_i=<path_to>/ventilatie.rrd:T_intake:AVERAGE " ..
" DEF:T_s=<path_to>/ventilatie.rrd:T_supply:AVERAGE " ..
" DEF:T_d=<path_to>/ventilatie.rrd:T_discharge:AVERAGE " ..
" DEF:T_e=<path_to>/ventilatie.rrd:T_exhaust:AVERAGE " ..
" --width 640" ..
" --height 240" ..
" --full-size-mode" ..
" --color BACK#243d47" ..
" --color CANVAS#243d47" ..
" --color FRAME#243d47" ..
" --color FONT#ffffff" ..
" --color AXIS#515d62" ..
" --color GRID#515d62" ..
" --color MGRID#515d62" ..
" --font TITLE:13:Arial" ..
" --font AXIS:10:Arial" ..
" --font LEGEND:9:Arial" ..
" --grid-dash 1:0" ..
" --border 0" ..
" --y-grid 10:1" ..
" LINE1:T_i#ff0000:' Invoer'" ..
" LINE1:T_s#0400ff:' Toevoer'" ..
" LINE1:T_d#aaff00:' Afvoer'" ..
" LINE1:T_e#35b73d:' Uitvoer'"

result = os.execute(rrdgraph)

-- move graph to web server
result = os.execute("sudo mv <path_to>/ventialtie.png /var/www/html/ventilatie")

Attached is the result.