4 Functions of the count inputs (CNT1 and CNT2)
4.2 Additional functions of the count inputs
XI/ON: XNE-2CNT-2PWM
04/2011 MN05002035Z-EN
www.eaton.com
53
Frequency measurement
In frequency measurement mode, the number of count pulses (content of REG_CNT1_IPI
(page 93)) within an integration time, which has to be defined (REG_CNT1_INTTIME
(page 93)), are measured. This integration time is parameterizable in steps of 10 ms/bit. An
integration time of max. 178 s is possible (a min. of 100 ms is reasonable).
→
After the integration time has expired, the result is calculated and entered into the register
interface.
Activation of the frequency measurement
The frequency measurement is activated, if:
CNTx_FQPD = 0
(
→
see Parameter data of the module, byte 0, bit2, page 25).
The frequency measurement is done in the following basic measurement modes:
• Calculation of the frequency in
mHz
:
• Calculation of the frequency in
Hz
:
Note
Changes in the count direction within the integration time cause errors in the fre-
quency measurement.
Input registers
Value
1
1
Integration time: Multiple of
10 ms
Output registers
Frequency in
mHz
Input registers
Value
1
1000
Integration time: Multiple of
10 ms
Output registers
Frequency in
Hz
Note
The accuracy of the measurement increases with the length of the integration time.
It should be noted that the measured value (REG_CNTx_MV) is only updated after
the integration time has expired.
Содержание XNE-2CNT-2PWM
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Страница 10: ...1 About this manual 1 3 Overview 10 XI ON XNE 2CNT 2PWM 04 2011 MN05002035Z EN www eaton com...
Страница 84: ...7 Report of configuration errors 7 1 Error register 84 XI ON XNE 2CNT 2PWM 04 2011 MN05002035Z EN www eaton com...