TAILIEUCHUNG - Microprocessor Interfacing Techniques Lab VIEW Tutorial Part 4

Microprocessor Interfacing Techniques Lab VIEW Tutorial Part 4 | PHY 406 - Microprocessor Interfacing Techniques PHY 406 - Microprocessor Interfacing Techniques LabVIEW Tutorial - Part IV Data Representations and Help Data Representations You should have on your diagram three colours of wire and three data types Orange Brown - with DBL boxes Blue - with I32 boxes Dotted Green - with TF boxes LabVIEW supports a large number of data types and their conversion. The major types of numeric variable are Abbreviation Type Storage Length Bytes Minimum Value Maximum Value EXT Extended Precision Real DBL Double Precision Real 8 SGL Single Precision Real 4 I32 Long Integer 4 I16 Word Integer 2 -32766 32767 I8 Byte Integer 1 -126 127 U32 Unsigned Long Integer 4 0 U16 Unsigned Word Integer 2 0 65535 U8 Unsigned Byte Integer 1 0 255 Since similar arithmetic operations can be performed on each of these types the arithmetic functions the controls and the indicators must be able to cope with these. To achieve this three different techniques are used changing type implicit type conversion and explicit type conversion. To see an example of the first and the second use the pop-up on the input control to the multiplier in your example to change the representation. Notice that the wires are orange brown for float and blue for integer unsigned. Notice also that if the input types to the multiplier are not James R. Drummond - September 1996 22 PHY 406 - Microprocessor Interfacing Techniques the same type then a black spot on the input indicates and implicit type conversion - the types of the inputs are changed to compatible types. To see an example of explicit conversion let s change the type of the output to a Word Integer. Remove the wires from the output of the multiplier to the chart and indicator by selecting them with the select tool and delete. Use Ctrl-B to clean up the broken wires. Now select functions numeric conversion To Word Integer and place the converter opposite the output of the multiplier. Complete the wiring from multiplier to input