Chapter 4
NI-DNET Programming Techniques
©
National Instruments Corporation
4-11
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];
