National Instruments NI-DNET - Manual (Page 42)

Chapter 4 NI-DNET Programming Techniques
© National Instruments Corporation 4-11 NI-DNET User Manual
4. 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. In
the front panel control that appears, you can use the button at index 0
to control Run Fwd and the button at index 2 to control Fault Reset.
6. Using the NI-DNET palette, place ncConvertForDnetWrite into
your diagram.
7. Wire the DnetData out terminal from the previous Convert into the
DnetData 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 Create
Control. You can use the front panel control that appears to change
Speed Reference.
11. Using the NI-DNET palette, place ncWriteDnetIO into your
diagram.
12. Wire the DnetData out terminal from the previous Convert into the
Data terminal of ncWriteDnetIO .
For more information on the ncConvertForDnetWrite and
ncConvertFromDnetRead functions, refer to the NI-DNET Programmer
Reference Manual. For information on LabVIEW data types and their
equivalent DeviceNet data types, refer to Chapter 1, NI-DNET Data Types,
in the NI-DNET Programmer Reference Manual.
Accessing I/O Members in C
Since DeviceNet data types are very similar to C language data types,
individual I/O members can be accessed in a straightforward manner. You
can use the standard C language pointer manipulations to convert between
C language data types and DeviceNet data types.
The following steps show an example of how standard C language can be
used to access the Basic Speed Control Output Assembly described in the
previous section.
1. Declare an array of 4 bytes, as in the following.
NCTYPE_UINT8OutputAsm[4];