{"id":38226,"date":"2024-02-12T20:02:35","date_gmt":"2024-02-12T20:02:35","guid":{"rendered":"https:\/\/www.alicat.com\/?post_type=article&p=38226"},"modified":"2026-02-03T20:49:18","modified_gmt":"2026-02-03T20:49:18","slug":"korrektur-der-durchflussdaten-nach-auswahl-eines-falschen-gases-in-der-gasauswahl","status":"publish","type":"support","link":"https:\/\/www.alicat.com\/de\/support\/correcting-flow-data-after-choosing-the-wrong-gas-in-gas-select\/","title":{"rendered":"Korrigieren von Durchflussdaten nach Auswahl des falschen Gases in Gas Select\u2122"},"content":{"rendered":"\n[et_pb_section fb_built=”1″ _builder_version=”4.23.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_row _builder_version=”4.23.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.23.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_heading title=”Correcting flow data after choosing the wrong gas in Gas Select\u2122” _builder_version=”4.23.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_heading][et_pb_text _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]

Selecting the correct pre-loaded gas calibration is an important step in obtaining accurate mass flow<\/a> data when using Alicat\u2019s laminar DP<\/a> mass flow meters and controllers. If you do notice you have been collecting data with the wrong gas selected, there is no need to panic. Data can easily be corrected using the instructions laid out in this article.<\/p>\n

Choosing the correct gas using Gas Select\u2122<\/h2>\n

The Gas Select\u2122<\/a> feature is built into the firmware of all Alicat laminar DP mass flow devices, enabling users to choose from a list of pre-loaded gas calibrations. To correct flow data and calibrate the instrument to the correct gas, simply scroll through Gas Select\u2122 and choose the right gas from the list.<\/p>\n

For example, suppose air is selected on a mass flow controller, but the actual gas flowing is Nat gas-2 (95% CH4<\/sub> + 3% C2<\/sub>H6<\/sub> + 1% N2<\/sub> + 1% CO2<\/sub>). As long as you have already defined the gas mixture using Composer\u2122<\/a>, you can select this Nat gas-2 instead of air and get the correct flow data.<\/p>\n

How is this correction made?<\/h3>\n

This correction is made by simply multiplying the incorrect reading by the ratio of the selected gas\u2019s viscosity and the desired gas\u2019s viscosity. See the equation below:<\/p>[\/et_pb_text][et_pb_accordion _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_accordion_item title=”Correction equation” open=”on” _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]

\"\"<\/strong><\/p>\n

Qindicated<\/sub><\/strong> = Recorded flow rate; \u03b7selected<\/sub><\/strong> = Absolute viscosity of incorrect gas;\u00a0\u03b7actual<\/sub>\u00a0<\/strong>= Absolute viscosity of the correct gas; Qactual<\/sub>\u00a0<\/strong>= Actual (corrected) flow rate<\/p>[\/et_pb_accordion_item][\/et_pb_accordion][et_pb_text _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]

Revisiting the above example, imagine you are flowing Nat gas-2 at 25\u00b0C and 1 SLPM. You accidentally have air selected, but realize it and switch to Nat gas-2. The gas tables<\/a> indicate that at 25\u00b0C, the viscosity of air is 184.8989 and the viscosity of Nat gas-2 is 111.55570.<\/p>\n

The device make the correction as follows:<\/p>\n

\"\"<\/p>\n

Flowing a gas that is not on the standard gas list<\/h2>\n

Imagine you are flowing a gas that is not available* in the standard gas list, such as water vapor**.<\/p>\n

Simply choose a gas that is\u00a0<\/em>available, such as air, and use the following equation to determine the proper setpoint to give the device:<\/p>\n

 <\/p>[\/et_pb_text][et_pb_accordion _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_accordion_item title=”Conversion equation” open=”on” _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]

\"\"<\/p>\n

Qinput <\/sub><\/strong>= Commanded setpoint; \u03b7selected<\/sub><\/strong> = Absolute viscosity of selected gas (i.e. air); \u03b7actual<\/sub>\u00a0<\/strong>= Absolute viscosity of flowing gas (i.e. water vapor); Qdesired<\/sub>\u00a0<\/strong>= Desired setpoint<\/p>[\/et_pb_accordion_item][\/et_pb_accordion][et_pb_text _builder_version=”4.25.1″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]

Water vapor has a viscosity at 25\u00b0C of 98.71700. For a setpoint of 25 SLPM of water vapor on a device that is set for air, calculate the input setpoint as follows:<\/p>\n

\"\"<\/p>\n

*If a gas is not available in the gas select menu on the screen, it might not be compatible with the wetted materials. Please contact Alicat<\/a> with any compatibility questions.<\/em><\/p>\n

**<\/em><\/strong>Water vapor is available as a custom software that our service department can program into our anti-corrosive devices.<\/em><\/p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]\n","protected":false},"featured_media":46458,"parent":0,"template":"","meta":{"_acf_changed":false,"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"1920","content-type":"","_searchwp_excluded":""},"categories":[],"class_list":["post-38226","support","type-support","status-publish","has-post-thumbnail","hentry"],"acf":[],"yoast_head":"\nCorrecting Flow Data After Choosing the Wrong Gas in Gas Select\u2122 - Alicat Scientific<\/title>\n<meta name=\"description\" content=\"Data taken with the wrong gas selected on your Alicat can easily be corrected using the instructions laid out in this article.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.alicat.com\/de\/unterstutzung\/korrektur-der-durchflussdaten-nach-auswahl-eines-falschen-gases-in-der-gasauswahl\/\" \/>\n<meta property=\"og:locale\" content=\"de_DE\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Correcting Flow Data After Choosing the Wrong Gas in Gas Select\u2122\" \/>\n<meta property=\"og:description\" content=\"Data taken with the wrong gas selected on your Alicat can easily be corrected using the instructions laid out in this article.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.alicat.com\/de\/unterstutzung\/korrektur-der-durchflussdaten-nach-auswahl-eines-falschen-gases-in-der-gasauswahl\/\" \/>\n<meta property=\"og:site_name\" content=\"Alicat Scientific\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/alicatscientific\/\" \/>\n<meta property=\"article:modified_time\" content=\"2026-02-03T20:49:18+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.alicat.com\/wp-content\/uploads\/2026\/01\/featured-alicat.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1200\" \/>\n\t<meta property=\"og:image:height\" content=\"630\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"4\u00a0Minuten\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.alicat.com\\\/support\\\/correcting-flow-data-after-choosing-the-wrong-gas-in-gas-select\\\/\",\"url\":\"https:\\\/\\\/www.alicat.com\\\/support\\\/correcting-flow-data-after-choosing-the-wrong-gas-in-gas-select\\\/\",\"name\":\"Correcting Flow Data After Choosing the Wrong Gas in Gas Select\u2122 - 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