Topic: DMD0143
SLOPE - Calculate Slope
The Calculate Slope (SLOPE) instruction is used to calculate the slope of the line between two points. The first point is the value of the specified input that is recorded when the instruction is enabled, the second point is recorded at the end of the Sample Time. Each time the calculation is made the first point is set equal to the second point and a new second point is recorded at the end of the next Sample Time. This process of computing the slope and shifting to the next point continues as long as the instruction is enabled.
Parameters:
Note: Use the F9 key or click the 'three dot box' at the right edge of the parameter field to open the Default Element Selection Tool (the Element Picker or the Element Browser) or use the Down-Arrow key (Auto-Complete) on any parameter field to see a complete list of the memory locations that are valid for that parameter of the instruction.
Input - specifies the numeric memory location that contains the value that is changing. This can be any readable numeric location.
Sample Time - specifies the period (in milliseconds) that the slope will be calculated while the instruction is enabled.
- Constant - specified using the Time format (HH : MM : SS : mmm). The maximum Sample Time value in this form is 569
hours, 31 minutes, 23 seconds, and 647 milliseconds. If needed, the value entered for the Cycle Time will be normalized to its standard value. For example,
if you entered a value of 97 Seconds, that value will be converted and displayed as 1 Minute and 37 Seconds. When editing the Constant Preset value,
these keystrokes are available to make entering the value easier and faster: h takes you to the Hours field,
m takes you to the Minutes field, s takes you to the Seconds field,
and mm takes you to the Milliseconds field.
- Variable - specifies a numeric memory location that contains the total number of milliseconds desired for the Sample Time. This can be any readable numeric location.
Slope - specifies the numeric memory location to store the calculated slope. This can be any writable numeric location.
Status Display:
The yellow triangle in the upper left corner indicates this is a Multi-Scan instruction.
See Also:
SLOPE- Calculate Slope
INTEGRAT - Integrate Over Time
Related Topics:
DEADBAND - Set Outside Deadband
PIDINIT - Set PID Tuning Constants
TIMEPROP - Time Proportional Control
Rung Example:
