L_USPP_Differentiate

This FB represents a differentiator with a low pass filter.

The input signal is differentiated and is filtered with the filter time constant defined via lrFilterTime .

The lrOut output signal has the unit [1/s] as time reference.

 

 

 

L_USPP_Differentiate

 

 

 

LREAL

-

lrIn

lrOut

-

LREAL

LREAL

-

lrFilterTime

 

 

 

 

 

 

 

 
Inputs

Name

Data type

Information/possible settings

lrIn

LREAL

Position input signal

lrFilterTime

LREAL

Filter time constant

  • Unit: s
  • Initial value: 0.0 (with this value, the filter is not active.)
  • If the value is lower or equals the task cycle time used, the filter is not active.
Outputs

Name

Data type

Value/meaning

lrOut

LREAL

Output signal (time reference [1/s])

Function

Considering the signalling technique, the FB consists of the series connection of a time-discrete differentiator and a PT1 filter.

Via the setting of the filter time constant (T filter ), filtering of the output signal can be switched off to '0.00 s' ( lrFilterTime = 0.0). In this case, the output signal directly results from:

function with an inactive filter ( lrFilterTime = 0.0)

With a switched-on filter ( lrFilterTime > 0.0), each change in the input signal is evaluated with 1 s/T filter , the output signal going back towards zero with the filter time constant (T filter ) afterwards.

function with an active filter ( lrFilterTime > 0.0)