WEG CFW300 V1.3X, Руководство по программированию

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Digital and Analog Inputs and Outputs
CFW300 | 12-9
12
12.4 FREQUENCY INPUT
A frequency input consists of a fast digital input able to convert the frequency of the pulses in the input into a
proportional signal with 15-bit resolution. After the conversion, this signal is used as an analog signal for frequency
reference, process variable, for example.
According to the block diagram of Figure 12.4 on page 12-9 , the signal in frequency is converted into a digital
quantity in 15 bits by means of the block "Calc. Hz / %", where parameters P248 and P250 define the input signal
frequency band, while parameter P022 shows the frequency of the pulses in Hz.
Function
FI - P246
Gain
FI - P247
Filter
P245
100 (%)
FI(%)
FI(Hz) - P022
FI(Hz)
Calc. Hz / %
(Hz)
P248
P250
Offset
FI - P249
Value FI
(internal)
Signal FI
(via DIx)
Figure 12.4: Block diagram of frequency input - FI (DIx)
Digital input DIx is pre-defined for frequency input via parameter P246, with operating capacity in a wide band
from 1 to 3000 Hz.
P022 - Value of Frequency Input
Adjustable
Range:
1 to 3000 Hz Factory
Setting:
Properties: ro
Description:
Value in hertz of the frequency input FI.
NOTE!
The operation of parameters P022 as well as of the frequency input, depends on the configuration
of the parameter P246.
P245 - Filter of the Frequency Input
Adjustable
Range:
0.00 to 16.00 s Factory
Setting:
0.00 s
Properties:
Description:
This parameter sets the time constant of the Frequency Input filter. It is intended to attenuate sudden changes
in its value.