ABB ACSM1 Series, Manual

Page: 392 / 510

Standard function blocks
392
Filters
FILT1
(10069)
Illustration
Execution time 7.59 µs
Operation The output (O) is the filtered value of the input (I) value and the previous output value
(O
prev
). The FILT1 block acts as 1st order low pass filter.
Note: Filter time constant (T1) must be selected so that T1/Ts < 32767. If the ratio
exceeds 32767, it is considered as 32767. Ts is the cycle time of the program in ms.
If T1 < Ts, the output value is the input value.
The step response for a single pole low pass filter is:
O (t) = I(t) × (1 - e
-t/T1
)
The transfer function for a single pole low pass filter is:
G(s) = 1/ (1 + sT1)
Inputs Input (I): REAL
Filter time constant input (T1): DINT, 1 = 1 ms
Outputs Output (O): REAL
FILT1
67
TLA1 1 msec (1)
I
T1
O
O(67)