Lenze DDS Function library Drive - Manual (Page 24)

2.2.8 Comparison (L_CMP)
Function library LenzeDrive.lib
Analog signal processing
2−14
L
LenzeDrive.lib EN 1.7
2.2.8.1 Function 1: nIn1_a = nIn2_a
·
Selection: byFunction = 1
·
This function compares two signals for equality. For instance, you can make the V comparison
"actual speed is equal to set speed" (n
act
= n
set
).
·
The exact function can be seen in the diagram. ( ^Fig. 2−12)
nWindow nWindow
1
0
nIn2_a nIn1_a
nHysteresis nHysteresis
nIn2_a
nHysteresis
nWindow
nHysteresis
nWindow
nIn1_a
bOut_b
t
t
Fig. 2−12 Equality of signals (nIn1_a = nIn2_a)
·
Use nWindow to set the window within which the equality is valid.
·
Use nHysteresis to set a hysteresis, if the input signals are not stable and the output oscillates.
Note!
With this function, you must use the FB in a fast task, to achieve optimum sampling of the signals.