DeviceNet NI-DNET User Manual

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Chapter 4 NI-DNET Programming Techniques

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];