Siemens SINAMICS S110 - DIF (Derivative Action Element)

Drive functions
7.3 Function modules
Function Manual
314 Function Manual, 01/2011, 6SL3097-4AB10-0BP3
7.3.8.24 DIF (derivative action element)
Brief description
Function block with derivative action behavior
Mode of operation
Output variable Y is proportional to the rate of change of input variable X multiplied by
derivative time constant TD.
The discrete values are calculated according to the following algorithm:
Yn = (Xn – Xn-1) · TD/TA
Y
n
Value of Y in sampling time n
X
n
Value of Y in sampling time n-1
X
n-1
Value of X in sampling time n
Note
The bigger TD/TA, the bigger the amplitude change on Y from one sampling time to the next.
TA is the configured sampling time of the function block.
TD is limited internally to TD ≥ 0.
Caution: Overcontrol possible!