We will create the “Input-Output” parameter tags.
- Let’s define an input tag as “Celsius”. Celsius will be configured as a REAL data type and as a Float style tag. The default value will be 0. The Required and Visibility column checkboxes will be checked because the tags are requiring an argument and will be visible on the AOI function when used in ladder logic. We’ll add a description “Celsius Temperature Input”, for users to understand the meaning of our input.
- We’ll define another input tag as “Fahrenheit_I”. It will be configured as a REAL data type and as a Float style tag. We’ll add a description “Fahrenheit Temperature Input”. Then we’ll set its External Access as Read Only.
- Now we will create the output parameters, “Fahrenheit_O” and “Kelvin” as REAL data types and as Float style tags. We will also add descriptions for both tags and make sure that their “External Access” will be configured as Read Only.
We will create three constants that will be used in our calculations. Let’s create “Constant_1”, “Constant_2”, and “Constant_3” as REAL data types and as Float style tags.
The default values will be respectively 1.8, 32, and 273.15.
The “Scan Modes” tab allows the designer to setup pre and post scan logic. We won’t be configuring these useful modes but will be explained.
- For the Prescan routine, the logic configured in this routine program is examined prior to the execution of the AOI. This allows for the AOI instruction a...
- The “Signature” tab allows the designer to prevent the AOI from modifications.
- The “Change History” tab displays the history of changes with names and dates and times.
- The “Help” tab will allow the user to create specific help text about the functions and logic used within the AOI.
