{"id":81,"date":"2021-06-30T10:43:30","date_gmt":"2021-06-30T10:43:30","guid":{"rendered":"http:\/\/nk-energi.dk\/?page_id=81"},"modified":"2021-07-28T14:12:17","modified_gmt":"2021-07-28T14:12:17","slug":"differenstrykmaler-sdp610","status":"publish","type":"page","link":"http:\/\/nk-energi.dk\/?page_id=81","title":{"rendered":"Differenstrykm\u00e5ler SDP810"},"content":{"rendered":"<p>Denne sider viser hvordan man tilslutter en differenstryksensor til en <a href=\"http:\/\/nk-energi.dk\/?page_id=21\">Raspberry Pi<\/a>. for at kunne forst\u00e5 denne gennemgang kr\u00e6ves der grundl\u00e6ggende viden omkring brug af <a href=\"http:\/\/nk-energi.dk\/?page_id=88\">Linux CLI<\/a>, download af <a href=\"http:\/\/nk-energi.dk\/?page_id=113\">libraries<\/a>, det vil ogs\u00e5 v\u00e6re en fordel at have lidt kendskab til <a href=\"http:\/\/nk-energi.dk\/?page_id=90\">Python programmering<\/a>. Her er et link til fabrikantens dokumentation: <a href=\"https:\/\/www.sensirion.com\/fileadmin\/user_upload\/customers\/sensirion\/Dokumente\/8_Differential_Pressure\/Datasheets\/Sensirion_Differential_Pressure_Datasheet_SDP8xx_Digital.pdf\" target=\"_blank\" rel=\"noopener\">Sensirion SDP810 datablad<\/a> i vejledningen er der taget udklip fra dokumentationen, for at give en forst\u00e5else for hvordan forbindelsen til sensoren virker. Sensoren er en digital <a href=\"http:\/\/nk-energi.dk\/?page_id=96\">I2C<\/a> sensor som er en meget anvendt <a href=\"http:\/\/nk-energi.dk\/?page_id=25\">protokol<\/a>.<\/p>\n<p>Her ses et diagram over hele ops\u00e6tningen, der skal bruges:<\/p>\n<ul>\n<li>breadboard<\/li>\n<li>2x 10k ohm modstande<\/li>\n<li>En Sensirion SDP810 sensor<\/li>\n<li>En Raspberry Pi<\/li>\n<li>jumper wires<\/li>\n<\/ul>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-227 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/Sensirion_SD810_diagram.png\" alt=\"\" width=\"1358\" height=\"605\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/Sensirion_SD810_diagram.png 1358w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/Sensirion_SD810_diagram-300x134.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/Sensirion_SD810_diagram-1024x456.png 1024w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/Sensirion_SD810_diagram-768x342.png 768w\" sizes=\"(max-width: 1358px) 100vw, 1358px\" \/><\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-221 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_opsaetning.png\" alt=\"\" width=\"1219\" height=\"654\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_opsaetning.png 1219w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_opsaetning-300x161.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_opsaetning-1024x549.png 1024w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_opsaetning-768x412.png 768w\" sizes=\"(max-width: 1219px) 100vw, 1219px\" \/><\/p>\n<p><img loading=\"lazy\" class=\"alignnone wp-image-222 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810pin_opsaetning.png\" alt=\"\" width=\"863\" height=\"539\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810pin_opsaetning.png 863w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810pin_opsaetning-300x187.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810pin_opsaetning-768x480.png 768w\" sizes=\"(max-width: 863px) 100vw, 863px\" \/><\/p>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>\n<ul>\n<li>Der skal bruges tre <a href=\"http:\/\/nk-energi.dk\/?page_id=113\">libraries<\/a> for at kunne m\u00e5le tryk.<\/li>\n<li>smbus skal importeres for at kunne transmittere data mellem SDP810 tryksensoren og Raspberry Pi.<\/li>\n<li>math skal importeres for at man kan omregne signalerne fra sensoren, til den enhed man \u00f8nsker at f\u00e5 signalet omregnet til.<\/li>\n<li>time skal bruges for at kunne f\u00e5 en pause mellem hver m\u00e5ling, s\u00e5 hukommelsen ikke bliver opbrugt med det samme.<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"wp-image-134 size-full alignleft\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b1.png\" alt=\"\" width=\"351\" height=\"68\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b1.png 351w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b1-300x58.png 300w\" sizes=\"(max-width: 351px) 100vw, 351px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>\n<ul>\n<li>Der laves en variable som hedder bus, denne laves ud af smbus.SMbus(1). Sensoren har adressen 0x25 denne laves der ogs\u00e5 en variabel til.<\/li>\n<li>Det f\u00f8rste signal som skrives til sensoren er: bus.write_i2c_block_data(address, 0x3F, [0xF9]), dette s\u00e6tter sensoren i tomgang. Signalet der bliver sendt best\u00e5r af adressen til sensoren og et register i sensoren som der interageres med.<\/li>\n<li>time.sleep(1) er en pause p\u00e5 et sekund som er n\u00f8dvendig for at sensoren kan blive klar til at modtage et nyt signal.<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-135 \" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b2.png\" alt=\"\" width=\"711\" height=\"69\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b2.png 891w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b2-300x29.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b2-768x74.png 768w\" sizes=\"(max-width: 711px) 100vw, 711px\" \/><\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-136 \" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b3.png\" alt=\"\" width=\"705\" height=\"163\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b3.png 846w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b3-300x70.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b3-768x178.png 768w\" sizes=\"(max-width: 705px) 100vw, 705px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>F\u00f8r man kan modtage m\u00e5linger fra fra SDP810 tryksensoren skal den indstilles til at m\u00e5le differenstryk. Dette g\u00f8res ved at man skriver: bus.write_i2c_block_data(address, 0x36, [0x1E]). Dette er det sidste step inden man kan begynde at l\u00e6se m\u00e5linger fra sensoren.<\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-137 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b4.png\" alt=\"\" width=\"697\" height=\"63\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b4.png 697w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b4-300x27.png 300w\" sizes=\"(max-width: 697px) 100vw, 697px\" \/><\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-138 \" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b5.png\" alt=\"\" width=\"672\" height=\"177\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b5.png 851w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b5-300x79.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b5-768x202.png 768w\" sizes=\"(max-width: 672px) 100vw, 672px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>\n<ul>\n<li>For at kunne f\u00e5 uendelig mange m\u00e5linger oprettes der et while loop.<\/li>\n<li>Der l\u00e6ses nu m\u00e5ledata fra SDP810 sensoren, ved at lave en variabel ud fra bus.read_i2c_block_data(address, 0, 9) denne kaldes datalist i dette tilf\u00e6lde. 9 er antallet af bytes som sensoren sender ud.<\/li>\n<li>De to f\u00f8rste bytes er differenstrykket, disse tages ud af listen og l\u00e6gges sammen. <a href=\"http:\/\/nk-energi.dk\/?page_id=25\">l\u00e6s mere om bits og bytes her.<\/a><\/li>\n<li>For at f\u00e5 m\u00e5ling omregnet til Pa skal min dividere med 240.<\/li>\n<li>N\u00e5r sensoren ikke m\u00e5ler sender den m\u00e5linger ud som viser max tryk(270+Pa), disse fejll\u00e6sninger fjernes ved skrive: if reading_dp&gt;270 :continue.<\/li>\n<li>print (reading_dp) viser m\u00e5leresultaterne.<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-207 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b6.png\" alt=\"\" width=\"511\" height=\"185\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b6.png 511w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b6-300x109.png 300w\" sizes=\"(max-width: 511px) 100vw, 511px\" \/><\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-144 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b7.png\" alt=\"\" width=\"492\" height=\"245\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b7.png 492w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b7-300x149.png 300w\" sizes=\"(max-width: 492px) 100vw, 492px\" \/><\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-140 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b8.png\" alt=\"\" width=\"638\" height=\"147\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b8.png 638w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b8-300x69.png 300w\" sizes=\"(max-width: 638px) 100vw, 638px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>Her ses hele programmet og nederst i tabellen ses programmet n\u00e5r det k\u00f8rer.<\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-206 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b9.png\" alt=\"\" width=\"878\" height=\"445\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b9.png 878w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b9-300x152.png 300w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp610b9-768x389.png 768w\" sizes=\"(max-width: 878px) 100vw, 878px\" \/><\/td>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" class=\"alignnone wp-image-142 size-full\" src=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b10.png\" alt=\"\" width=\"537\" height=\"99\" srcset=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b10.png 537w, http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/06\/sdp610b10-300x55.png 300w\" sizes=\"(max-width: 537px) 100vw, 537px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<table style=\"width: 120%; text-align: left; background-color: lightgrey;\">\n<tbody>\n<tr>\n<td>Instaler smbus library og inds\u00e6t koden i nano p\u00e5 din Raspberry Pi<\/td>\n<\/tr>\n<tr>\n<td>$ sudo apt-get install python-smbus python3-smbus python-dev python3-dev i2c-tools<\/td>\n<\/tr>\n<tr>\n<td><a href=\"http:\/\/nk-energi.dk\/wp-content\/uploads\/2021\/07\/sdp810_kode.rtf\" target=\"_blank\" rel=\"noopener\">kode til SDP810<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>Denne sider viser hvordan man tilslutter en differenstryksensor til en Raspberry Pi. for at kunne forst\u00e5 denne gennemgang kr\u00e6ves der grundl\u00e6ggende viden omkring brug af Linux CLI, download af libraries, det vil ogs\u00e5 v\u00e6re en fordel at have lidt kendskab &hellip; <a href=\"http:\/\/nk-energi.dk\/?page_id=81\">L\u00e6s resten <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"onecolumn-page.php","meta":[],"_links":{"self":[{"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/pages\/81"}],"collection":[{"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/nk-energi.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=81"}],"version-history":[{"count":93,"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/pages\/81\/revisions"}],"predecessor-version":[{"id":549,"href":"http:\/\/nk-energi.dk\/index.php?rest_route=\/wp\/v2\/pages\/81\/revisions\/549"}],"wp:attachment":[{"href":"http:\/\/nk-energi.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=81"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}