{"id":21299,"date":"2017-07-24T09:44:50","date_gmt":"2017-07-24T16:44:50","guid":{"rendered":"https:\/\/blog.digilentinc.com\/?p=21299"},"modified":"2021-06-10T16:35:36","modified_gmt":"2021-06-10T23:35:36","slug":"labview-formula-nodes","status":"publish","type":"post","link":"https:\/\/digilent.com\/blog\/labview-formula-nodes\/","title":{"rendered":"LabVIEW Formula Nodes"},"content":{"rendered":"

The Formula Node in the LabVIEW software is a convenient, text-based node you can use to perform complicated mathematical operations on a block diagram using the C++ syntax structure. It is most useful for equations that have many variables or are otherwise complicated. The text-based code simplifies the block diagram and increases its readability. Furthermore, you can copy and paste existing code directly into the Formula Node rather than recreating it graphically.<\/p>\n

\"\"<\/p>\n

In addition to text-based equation expressions, the Formula Node can accept text-based versions of if statements, while loops, for loops, and do loops, which are familiar to C programmers. These programming elements are similar but not identical to those you find in C programming.<\/p>\n

Using the Formula node<\/strong><\/p>\n

Complete the following steps to create a VI that computes different formulas depending on whether the product of the inputs is positive or negative.<\/p>\n

    \n
  1. Selecting\u00a0File<\/b>\u00bbNew VI<\/b>\u00a0to open a blank VI.<\/li>\n
  2. Place a Formula Node on the block diagram.\n
      \n
    1. Right-click on the diagram and navigate to\u00a0Programming<\/b>\u00bbStructures<\/b>\u00bbFormula Node<\/b>.<\/li>\n
    2. Click and drag the cursor to place the Formula Node on the block diagram.<\/li>\n<\/ol>\n<\/li>\n
    3. Right-click the border of the Formula Node and select\u00a0Add Input<\/b>\u00a0from the shortcut menu.<\/li>\n<\/ol>\n

      \"\"<\/p>\n

        \n
      1. Label the input variable\u00a0x.<\/span><\/li>\n
      2. Repeat steps 3 and 4 to add another input and label it\u00a0y<\/span>.<\/li>\n
      3. Right-click the border of the Formula Node and select\u00a0Add Output<\/b>\u00a0from the shortcut menu.<\/li>\n<\/ol>\n

        \"\"<\/p>\n

          \n
        1. Create two outputs and name them\u00a0z1<\/span><\/i>\u00a0and\u00a0z2<\/span><\/i>, respectively.<\/li>\n<\/ol>\n

          \"\"<\/b><\/p>\n

            \n
          1. Enter the expressions below in the Formula Node. Make sure that you complete each command with a semicolon. Notice, however, that the if statement does not require a semicolon after the first line.<\/li>\n<\/ol>\n

            if (x*y>0)
            \nz1 = 3*x**2 – 2*y**3;
            \nelse z1 = 0;
            \nz2 = sinh(z1);<\/p>\n

              \n
            1. Create controls and indicators for the inputs and outputs.\n
                \n
              1. Right-click on each input and select\u00a0Create<\/b>\u00bbControl<\/b>\u00a0from the shortcut menu.\"\"<\/li>\n
              2. Right-click on each output and select\u00a0Create<\/b>\u00bbIndicator<\/b>\u00a0from the shortcut menu.<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n

                \"\"<\/p>\n

                  \n
                1. Place a While Loop with a stop button around the Formula Node and the controls. Be sure to include a Wait (ms) function inside the loop to conserve memory usage. Your block diagram should appear as follows<\/li>\n<\/ol>\n

                  \"\"<\/p>\n

                    \n
                  1. Click the\u00a0Run<\/b>\u00a0button to run the VI. Change the values of the input controls to see how the outputs change.<\/li>\n<\/ol>\n

                    In this case, the Formula Node helps minimize the space required on the block diagram. Accomplishing the same task without the use of a Formula Node requires the following code.<\/p>\n

                    \"\"<\/p>\n

                    Thank you for reading my blog post, and for more information on\u00a0formula nodes follow this\u00a0link<\/a>. If you are interested in trying out LabVIEW for yourself, you can purchase a copy of\u00a0LabVIEW 2014 Home Edition<\/a>\u00a0which includes everything you will need to run\u00a0LINX 3.0<\/a>.\u00a0Please comment below with any questions or comments you may have.<\/p>\n

                    0<\/span><\/a><\/div><\/div>
                    <\/div><\/div>
                    <\/div>","protected":false},"excerpt":{"rendered":"

                    Austin makes LabVIEW even more efficient with formula nodes!<\/p>\n","protected":false},"author":42,"featured_media":21484,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4323],"tags":[],"ppma_author":[4493],"class_list":["post-21299","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-software"],"jetpack_featured_media_url":"https:\/\/digilent.com\/blog\/wp-content\/uploads\/2017\/07\/yoynkmfs49136.jpg","jetpack_sharing_enabled":true,"authors":[{"term_id":4493,"user_id":42,"is_guest":0,"slug":"astanton","display_name":"Austin Stanton","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/0cc9db2caf6344c8f78ea46c21570f33a954c45596addf479125043e52431de0?s=96&d=mm&r=g","1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":"","9":"","10":""}],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts\/21299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/users\/42"}],"replies":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/comments?post=21299"}],"version-history":[{"count":0,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts\/21299\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/media\/21484"}],"wp:attachment":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/media?parent=21299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/categories?post=21299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/tags?post=21299"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/ppma_author?post=21299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}