| Function Name |
SUB_TOD_TOD |
|---|---|
|
Description |
Subtracts a time of day input from a time of day input to provide a time output. |
|
Arguments |
Input 1 {TIME_OF_DAY} Input 2 {TIME_OF_DAY} For more information on the data types for the inputs and outputs, see Data Type Hierarchy. |
|
Returns |
Output {TIME} The Output is the result of Input 1 - Input 2 |
Example:
Function Block Diagram - SUB_TOD_TOD:
A NOW function is used to provide the current time for a SUB_TOD_TOD function. As the NOW function provides a date time value, a DT_TO_TOD function has to be used to convert the NOW output into a TOD value that can be used as an input by the SUB_TOD_TOD function.
For its other input, the SUB_TOD_TIME function has a constant that is set to TOD#16:00:23.144:
The SUB_TOD_TIME function returns a time value that is the result of the current time - 16:0023:144, that is, the difference in time between the current time and 16:0023:144.
ST Program - SUB_TOD_TOD:
The syntax for a SUB_TOD_TOD function in an ST Program is:
- Output := SUB_TOD_TOD (Input 1, Input 2)
Where Output, Input 1 and Input 2 are defined as variables earlier in the ST program. Input 1 is a time of day value, Input 2 is a time of day value, and the Output is a time value.