[hobbit] graph positive and negative values

[Benjamin P. August]

Is there any way to get the sensors to output in Kelvin?


----- Message from mjtice at gmail.com -----


> Hi, I'm wondering if anyone has been successful setting up and graphing an
> item that fluctuates between positive and negative values?  I'm trying to
> trend the temperature of my freezer.  When I created the rrd earlier today
> (when positive values were generated) the graph was functional.  When I put
> my sensors inside the freezer (where the temperatures drop a few degrees
> below zero F) the values wouldn't drop below zero on the graph.
> I tried modifying the current rrd tool with:
> rrdtool tune /home/hobbit/data/rrd/tice/freezer.rrd --minimum freezerf:U
> (which did drop the minimum to nan) but I still couldn't get negatives to
> show on the graph.  I thought I'd delete the rrd and start over - but I
> think now that the values are negative numbers the rrd won't even create.
>  Here is a snippet from my hobbitgraph and hobbitserver files
>
> [freezer]
>        TITLE Freezer Temperature
>        YAXIS Degrees
>        DEF:tl=freezer.rrd:freezerf:AVERAGE
>        #CDEF:wipeoutf=tl,-1,*
>        DEF:cel=freezer.rrd:freezerc:AVERAGE
>        #CDEF:wipeoutc=cel,-1,*
>        LINE2:tl#@COLOR@:Temperature F
>        #LINE2:wipeoutf#@COLOR@:Temperature -F
>        LINE2:cel#@COLOR@:Temperature C
>        #LINE2:wipeoutc#@COLOR@:Temperature -C
>        COMMENT:\n
>        GPRINT:tl:LAST:Temperature F\: %2.1lf (cur)
>        GPRINT:tl:MAX:\: %2.1lf (max)
>        GPRINT:tl:MIN:\: %2.1lf (min)
>        GPRINT:tl:AVERAGE:\: %2.1lf (avg)\n
>        GPRINT:cel:LAST:Temperature C\: %2.1lf (cur)
>        GPRINT:cel:MAX:\: %2.1lf (max)
>        GPRINT:cel:MIN:\: %2.1lf (min)
>        GPRINT:cel:AVERAGE:\: %2.1lf (avg)\n
>
>
> NCV_freezer="*:GAUGE"
> (with freezer=ncv at the end of TEST2RRD and freezer and the end of GRAPHS).
>
> Here is my script that generates the NCV for the rrd:
>
> #!/bin/sh
> COLUMN=freezer      # Name of the column
> COLOR=green     # By default, everything is OK
>
> [ -f ./.digitemprc ] || /usr/local/bin/digitemp_DS9097U -s/dev/ttyS0 -i
>
> TEMPERATURE=$(/usr/local/bin/digitemp_DS9097U -s/dev/ttyS0 -a | awk '{print
> $9}' | tail -1 | awk -F. '{print $1}')
>
> if [ "${TEMPERATURE}" -gt 30 ]; then
> COLOR=red
> MSG="Temperature above 30 degrees"
> else
> COLOR=green
> MSG="Temperature normal"
> fi
>
> # Section for data graphing
> TEMPERATURE2_F=$(/usr/local/bin/digitemp_DS9097U -s/dev/ttyS0 -a | awk
> '{print $9}' | tail -1)
> TEMPERATURE2_C=$(/usr/local/bin/digitemp_DS9097U -s/dev/ttyS0 -a | awk
> '{print $7}' | tail -1)
>
> echo "freezerf : ${TEMPERATURE2_F}" > $BBTMP/freezer_f.txt
> echo "freezerc : ${TEMPERATURE2_C}" > $BBTMP/freezer_c.txt
> ##
>
>
> $BB $BBDISP "status $MACHINE.freezer $COLOR $MSG
> `cat $BBTMP/freezer_f.txt`
> `cat $BBTMP/freezer_c.txt`
> "
>
> rm $BBTMP/freezer_f.txt
> rm $BBTMP/freezer_c.txt
>
> exit 0
>
>
> If anyone has an idea please let me know - I'd really like to trend this
> data.
>
> Thanks,
>
> Matt
>


-- 
--Ben 
Benjamin P. August
System Administrator - VPUE
Stanford University