National Instruments NI-DNET User Manual

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National Instruments NI-DNET User Manual Manual pdf 42 page image

Chapter 4 NI-DNET Programming Techniques© National Instruments Corporation 4-11 NI-DNET User Manual4. Right-click on the ByteOffset terminal and select Create Constant,then enter 0 as the byte offset.5. Right-click on the 8[TF] in terminal and select Create Control. Inthe front panel control that appears, you can use the button at index 0to control Run Fwd and the button at index 2 to control Fault Reset.6. Using the NI-DNET palette, place ncConvertForDnetWrite intoyour diagram.7. Wire the DnetData out terminal from the previous Convert into theDnetData in terminal of this Convert.8. Right-click on the DnetType terminal and select Create Constant,then select INT from the enumeration.9. Right-click on the ByteOffset terminal and select Create Constant,then enter 2 as the byte offset.10. Right-click on the I32/I16/I8 in terminal and select CreateControl. You can use the front panel control that appears to changeSpeed Reference.11. Using the NI-DNET palette, place ncWriteDnetIO into yourdiagram.12. Wire the DnetData out terminal from the previous Convert into theData terminal of ncWriteDnetIO.For more information on the ncConvertForDnetWrite andncConvertFromDnetRead functions, refer to the NI-DNET ProgrammerReference Manual. For information on LabVIEW data types and theirequivalent DeviceNet data types, refer to Chapter 1, NI-DNET Data Types,in the NI-DNET Programmer Reference Manual.Accessing I/O Members in CSince DeviceNet data types are very similar to C language data types,individual I/O members can be accessed in a straightforward manner. Youcan use the standard C language pointer manipulations to convert betweenC language data types and DeviceNet data types.The following steps show an example of how standard C language can beused to access the Basic Speed Control Output Assembly described in theprevious section.1. Declare an array of 4 bytes, as in the following.NCTYPE_UINT8OutputAsm[4];