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<document xmlns="http://cnx.rice.edu/cnxml" xmlns:md="http://cnx.rice.edu/mdml/0.4" xmlns:m="http://www.w3.org/1998/Math/MathML" xmlns:bib="http://bibtexml.sf.net/" id="None">
  <name>Formula Node</name>
  <metadata>
  <md:version>**new**</md:version>
  <md:created>2004/06/24 10:37:00.796 GMT-5</md:created>
  <md:revised>2004/06/24 10:38:06.243 GMT-5</md:revised>
  <md:authorlist>
      <md:author id="NationalInstruments">
      <md:firstname>National</md:firstname>
      
      <md:surname>Instruments</md:surname>
      <md:email>certification@ni.com</md:email>
    </md:author>
  </md:authorlist>

  <md:maintainerlist>
    <md:maintainer id="mshiralkar05">
      <md:firstname>Malan</md:firstname>
      
      <md:surname>Shiralkar</md:surname>
      <md:email>mshiralkar05@hotmail.com</md:email>
    </md:maintainer>
    <md:maintainer id="harika">
      <md:firstname>Harika</md:firstname>
      
      <md:surname>Basana</md:surname>
      <md:email>ilsai@rice.edu</md:email>
    </md:maintainer>
    <md:maintainer id="lizzardg">
      <md:firstname>Elizabeth</md:firstname>
      
      <md:surname>Gregory</md:surname>
      <md:email>lizzardg@rice.edu</md:email>
    </md:maintainer>
    <md:maintainer id="NationalInstruments">
      <md:firstname>National</md:firstname>
      
      <md:surname>Instruments</md:surname>
      <md:email>certification@ni.com</md:email>
    </md:maintainer>
  </md:maintainerlist>
  
  <md:keywordlist>
    <md:keyword>National Instruments</md:keyword>
    <md:keyword>LabVIEW</md:keyword>
    <md:keyword>node</md:keyword>
  </md:keywordlist>

  <md:abstract>In this lesson, you will learn how to use the Formula Node.</md:abstract>
</metadata>

  <content>
    <para id="p1">
      Use the <code>Formula Node</code> to perform mathematical
      operations in the LabVIEW environment. For additional
      functionality, you can link to the mathematics application
      MATLAB®.
    </para>
    <section id="s1">
      <name>Formula Node</name>
      <para id="s1p1">
	The <code>Formula Node</code> is a convenient text-based node
	you can use to perform mathematical operations on the block
	diagram. <code>Formula Nodes</code> are useful for equations
	that have many variables or are otherwise complicated and for
	using existing text-based code. You can copy and paste the
	existing text-based code into a <code>Formula Node</code>
	rather than recreating it graphically on the block diagram.
      </para>
      <para id="s1p2">
	Create the input and output terminals of the <code>Formula
	Node</code> by right-clicking the border of the node and
	selecting <code>Add Input</code> or <code>Add Output</code>
	from the shortcut menu, then enter the variable for the input
	or output. Type the equation in the structure. Each equation
	statement must terminate with a semicolon (<code>;</code>).
      </para>
      <para id="s1p3">
	<code>Formula Nodes</code> also can be used for decision
	making. The block diagram shown in <cnxn target="s1f1"/> shows
	two different ways of using an <code>if-then</code> statement
	in a <code>Formula Node</code>. The two structures produce the
	same result.
      </para>
      <figure id="s1f1">
	<media type="image/png" src="formnodeex.png"/>
      </figure>
      <para id="s1p4">
	The <code>Formula Node</code> can perform many different
	operations. Refer to the <cite>LabVIEW Help</cite> for more
	information about functions, operations, and syntax for the
	<code>Formula Node</code>.
      </para>
      <note>
	The <code>Formula</code> Express VI located on the
	<code>Functions&gt;&gt;Arithmetic &amp; Comparison</code> palette
	uses a calculator interface to create mathematical
	formulas. You can use this Express VI to perform most math
	functions that a basic scientific calculator can compute.
	Refer to the <cite>LabVIEW Help</cite> for more information
	about the <code>Formula</code> Express VI.
      </note>
    </section>

  </content>
  
</document>
