Defining Data Types

For better readability and programming, we will define data types that correspond to our assembly structures. First we will define a new String type that has space for 28 characters, the same as we defined in our assemblies. Right click on Data Types -> Strings in the tree and select New String Type....

FIGURE F-26. 

Name the string and set the Maximum Characters to 28. Including the 4 bytes of string length data, this will result in a total data size of 32 bytes.

FIGURE F-27. 

Next, we will create a data structure to represent the results we will be receiving from the VS-1 Smart Camera in the input assembly.

First, define the structure of a Point that is composed of 3 floating point numbers. Right click on Data Types -> User-Defined to create the Point type. Add three Members of type REAL to hold the X, Y and angle values of the point. The total structure size should be 12 bytes.

FIGURE F-28. 

Next, create the structure representing the input assembly contents. Again, right click on Data Types -> User Defined and select New Data Type. Add the data types in the same order as we previously defined the assemblies to be.

• A User Tag of type DINT.

• The Center Point of the decoded DMR that is of our newly defined type Point, composed of three floats.

• Decoded String which is our new VS-1 Smart Camera String type of 28 characters.

• DMR Status of type DINT which will contain the pass/fail status of the Data Matrix Tool.

Once completed, the full input assembly data type should total 52 bytes and appear as shown in (Figure F-29).

FIGURE F-29.