PLC Ramp

A Ramp brings a Output value up or down at a set rate.

Data Used in Simple Ramp:

  • Output that will be raised or lowered (Integer or Float)
  • Acceleration/Deceleration¬†Rate (Integer or Float). ¬†Typically measured in Units/Sec¬≤
  • Acceleration Input
  • Deceleration Input

In this example we see that:

  • Output Rises when Acceleration Input (Up Arrow) is high
  • Output Lowers¬†when¬†Deceleration¬†Input (Down Arrow) is high
  • Output remains¬†steady¬†nothing when both Acceleration and Deceleration Input are low or high.
  • Though not obvious in this example, Acceleration/Deceleration Rate controls the steepness of the rise & fall in output value.

Now lets look at a more sophisticated Ramp. ¬†We’ll add the following options:

  • Maximum & Minimum ¬†(Integer or Float)
  • Soft Start Time (Integer or Float) typically measured in ms. ¬†This is the time taken to transition from steady state to Acceleration/Deceleration Rate. ¬†This can reduce the stress on motors.
In this example we see:
  • Once the Maximum is reached, the Output quits Rising, even when the Acceleration Input is High. ¬†Similar behavior would occur for Minimum if it were included in the example.
  • Including Soft Start Time lengthens the amount of time it takes to reach a value.