{"id":130,"date":"2008-05-21T00:23:25","date_gmt":"2008-05-20T22:23:25","guid":{"rendered":"http:\/\/www.doenges.com\/blog\/?p=130"},"modified":"2009-01-21T18:07:37","modified_gmt":"2009-01-21T17:07:37","slug":"voltcraft-k204-datalogger-on-mac-os-x","status":"publish","type":"post","link":"https:\/\/doenges.com\/blog\/2008\/05\/21\/voltcraft-k204-datalogger-on-mac-os-x","title":{"rendered":"Voltcraft K204 Datalogger on Mac OS X"},"content":{"rendered":"

Conrad Electronic sell the Voltcraft K204<\/a> datalogger, which is a 4 channel temperature logger. [Note that the above link is to the German Conrad website. The links to other sites are, unfortunately, not the same, so you will have to perform a search on each national site.]<\/p>\n

The logger allows you to capture up to 16,000 samples from up to four different K-Type temperature probes. Depending on the probes, a temperature range of -200\u00b0C (-328\u00b0F) to 1370\u00b0C (2498\u00b0F) may be covered with a 0.1\u00b0C resolution.<\/p>\n

The K204 sports a serial port and comes with a RS232 cable. No Macintosh computer has come with a RS232 port for the last … what … decade or so?<\/p>\n

Fortunately for me, Conrad also sell a USB adapter<\/a> for the device. Unfortunately, but predictably, only Microsoft Windows compatible software is included on the CD.<\/p>\n

I plugged the USB adapter in and checked the device ID. It turns out that the adapter is basically a Silicon Labs<\/a> CP2102 USB to UART bridge<\/a> .\u00a0Silicon Labs provide a number of drivers<\/a> , including a Linux and a Mac OS X driver for the device. Conrad provide a brief description of the communications protocol<\/a> used by the K204. That is what I call useful customer support!<\/p>\n

After a couple of hours of work, most of which where spent figuring out the differences between the protocol description and the real protocol, I had a working application to read all data samples from the device on Mac OS X.<\/p>\n

It is very simple to use:<\/p>\n

1. Open a Terminal.app.<\/p>\n

2. Type:<\/p>\n

> k204\u00a0\/dev\/tty.SLAB_USBtoUART dumpfile.txt<\/code><\/p>\n

where \/dev\/tty.SLAB_USBtoUART<\/code> is the serial device created by the driver and dumpfile.txt<\/code> is the file you want to create.<\/p>\n

This will create a file\u00a0with content similar to this sample:
\nData Set:\t1
\nSample start:\t2008-05-02 17:56:18
\nSample interval in seconds:\t60
\nSensor type:\tK-Type
\nTemperature unit:\tCelsius
\nNumber of sample sets:\t16000
\nData Set\tCH1\tCH2\tCH3\tCH4
\n2008-05-02 18:56:18\t25.2\t26.5\t46.5\t17.1
\n2008-05-02 18:57:18\t25.1\t26.5\t46.5\t17.1
\n2008-05-02 18:58:18\t25.1\t26.6\t46.5\t17.1
\n2008-05-02 18:59:18\t25.2\t26.6\t46.5\t17.0
\n2008-05-02 19:00:18\t25.1\t26.6\t46.5\t17.0
\n2008-05-02 19:01:18\t25.2\t26.5\t46.5\t17.0
\n2008-05-02 19:02:18\t25.2\t26.6\t46.5\t17.0
\n2008-05-02 19:03:18\t25.2\t26.4\t46.5\t17.0<\/code><\/p>\n

Note that you may have multiple data sets, depending on how and what you captured. In this case, you will have multiple Data Set:<\/code> headers.
\nThe fields are TAB (‘\\t’) separated.<\/p>\n

3. You can remove the header from the file using a text editor or by using the shell command<\/p>\n

tail -n +7 dumpfile.txt >dumpfile.tsv<\/code><\/p>\n

4. Your favorite data display tool will now render the file. You can use OpenOffice\/NeoOffice or Excel or whatever. I like using gnuplot<\/a> :<\/p>\n

# Plot data downloaded from K204 Thermologger
\n# These settings are optimized for use with the PostScript driver.
\n<\/code><\/p>\n

# define line styles
\nset style line 1 linetype 1 linecolor rgb "red" linewidth 1
\nset style line 2 linetype 2 linecolor rgb "dark-red" linewidth 1
\nset style line 3 linetype 3 linecolor rgb "orange" linewidth 2
\nset style line 4 linetype 4 linecolor rgb "blue" linewidth 1
\nset style data fsteps
\n<\/code><\/p>\n

set xlabel "Date\\Time"
\nset timefmt "%Y-%m-%d %H:%M:%S"\t#2008-03-21 13:20:00
\nset yrange [ 0 : 80 ]
\nset xdata time
\n#set xrange [ "2008-03-25 15:28:19":"2008-03-26 20:52:54" ]
\nset ylabel "Temperature\\n\u00b0 C"
\nset format x "%d.%m.%y\\n%H:%M:%S"
\nset key inside left top vertical Right noreverse enhanced autotitles nobox
\nset style data fsteps
\n<\/code><\/p>\n

set grid nopolar
\nset grid xtics nomxtics ytics nomytics noztics nomztics \\
\nnox2tics nomx2tics noy2tics nomy2tics nocbtics nomcbtics
\nset grid layerdefault linetype 0 linewidth 1.000, linetype 0 linewidth 1.000
\n<\/code><\/p>\n

set title "02-MAY-2008 18:56 - 02-MAY-2008 21:35"
\nplot "dumpfile.tsv" using 1:3 title "T_{1}" linestyle 1, \\
\n"dumpfile.tsv" using 1:4 title "T_{2}" linestyle 2, \\
\n"dumpfile.tsv" using 1:5 title "T_{3}" linestyle 3, \\
\n"dumpfile.tsv" using 1:6 title "T_{4}" linestyle 4<\/code><\/p>\n

Which gives you this – admittedly somewhat boring, but rather good-looking – plot:<\/p>\n

\"gnuplot<\/p>\n

Congratulations, you have made it this far, so here is your reward: I am releasing the sources<\/a> under a BSD-style license<\/a> .<\/p>\n

The sources compile and run under Mac OS X 10.4.9 and later. I have not tried 10.5 yet, but I see no reason why there should be a problem.<\/p>\n

Update:<\/strong> It works just fine under 10.5. \ud83d\ude42<\/p>\n

Similarly, I fully expect the program to compile and run under most BSD or Unix variants (including Linux), providing they support the tcgetattr()<\/tt> \/tcsetattr()<\/tt> options used.<\/p>\n

I am very interested in hearing from you if you deployed the program on other platforms. Drop me a line or submit a comment and, most importantly, share your modifications so that everyone can profit. Have fun!<\/p>\n

Update 21-JAN-2009:<\/strong> Silicon Labs have changed the links on their website, so I changed mine. Come on guys, how long have you been at this web game?<\/p>\n","protected":false},"excerpt":{"rendered":"

Conrad Electronic sell the Voltcraft K204 datalogger, which is a 4 channel temperature logger. [Note that the above link is to the German Conrad website. The links to other sites are, unfortunately, not the same, so you will have to perform a search on each national site.] The logger allows you to capture up to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[670,666,667,715,104,669,577,668,665,671],"class_list":["post-130","post","type-post","status-publish","format-standard","hentry","category-software","tag-bsd","tag-datalogger","tag-driver","tag-gnuplot","tag-mac-os-x","tag-open-source","tag-software","tag-source-code","tag-temperature","tag-unix"],"_links":{"self":[{"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/posts\/130","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/comments?post=130"}],"version-history":[{"count":4,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/posts\/130\/revisions"}],"predecessor-version":[{"id":335,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/posts\/130\/revisions\/335"}],"wp:attachment":[{"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/media?parent=130"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/categories?post=130"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/doenges.com\/blog\/wp-json\/wp\/v2\/tags?post=130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}