Logical functions, Excel

The Excel logical AND and IF functions are used to automatically highlight the solvents that meet these targets. 

There are several useful logical functions in Excel. IF is a common feature. Figure A. 12 represents the function =IF(A1[Pg.435]

Logical functions allow you to use different formulas in a cell, depending on the values in other cells. The logical functions provided with Excel are IF, AND, OR and NOT. The latter three are almost always used in combination with the IF function, as are the comparison operators. 

In early spreadsheet programs, a macro was simply a string of keystrokes that could be recorded, saved and repeated to automate a simple keyboard operation. In Microsoft Excel, macros are written in a complete programming language that provides the capability to perform iterative calculations, or to take different actions based on the results of logic functions. 

In this section, we will look at some of Excel s logical functions. These are functions that allow you to test various conditions when programming formulas to analyze data. Excel s logical functions and their descriptions are shown in Table 14.6. 

Excel also offers relational or comparison opetacois that allow for testing of relative magnitude of various arguments. These relational operators are shown in Table 14.7. We will use Example 14.5 to demonstrate the use of Excel s logical functions and relational operators. 

Using Excel s logical functions, create a list that shows the correspondii open and closed position of the check valve (see Figure 14.9). 

Being excellent at discrete logic, PLCs are a potential candidate for implementing interlocks. Process interlocks are clearlv acceptable for implementation within a PLC. Implementation of safety interlocks in programmable electronic systems (such as a PLC) is not universally accepted. Many organizations continue to require that all safety interlocks be hard-wired, but implementing safety interlocks in a PLC that is dedicated to safety functions is accepted by some as being equivalent to the hard-wired approach. 

Excel 2000 provides more than 300 worksheet functions, in 11 categories Engineering, Financial, Date Time, Information, Math Trig, Statistical, Lookup Reference, Database, Text, Logical, External. This book uses functions from seven of those categories. This appendix lists selected worksheet functions by category. In Appendix B, the functions are listed alphabetically, with comments, examples and related functions. 

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