Commissioning
EL5101, EL5101-0010, EL5101-0011
132
Version: 4.2
Notes
Frequency
• The time window for the frequency calculation and the resolution can be parameterized in CoE objects
0x80n0:11 [
}
139]
,
0x80n0:13 [
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,
0x80n0:15 [
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,
0x80n0:17 [
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.
• The positive edges of track A are counted within the specified timeframe and the next edge including
the time up to it are counted. The waiting time can be set in CoE object 0x80n0:17 “Frequency Wait
Time” (unit: ms). The default value is 1.6 sec. This is also the maximum value.
• The time window is 10 ms (default), min. 1 µs. With the default setting it is possible to measure
frequencies up to approx. 800 kHz. At higher frequencies a smaller value must be selected for the
timeframe.
• The time is measured with a resolution of 100 ns.
• This calculation is carried out in the slave without reference to the distributed clocks system. It is
therefore independent of the DC mode.
• No frequency measurement is possible if the counter is blocked by the gate. In this case the period can
be measured regardless.
• If an encoder signal only is only present at input A/A and the frequency/period is to be measured, the
terminal must be set to “Up/Down Counter” in CoE
0x8010:03 [
}
139]
.
• A C or external reset restarts the frequency measurement. The last frequency value remains
unchanged until a new frequency value is determined.
Frequency measurement
• Basic unit 1 µs: all window sizes
Measurement sequence
• The measurement starts with a positive edge at track A. The current counter value and time
(resolution: 100 ns) are stored.
• After the measuring window time has elapsed (index
0x80n0:11 [
}
139]
), the system waits for the
following rising edge at track A or a maximum of 1.6 sec or the time from
0x80n0:17 [
}
139]
• The frequency is calculated from the edge difference and the actual elapsed time.
Fig. 156: Frequency measurement principle in enhanced operation mode
Period calculation
• This calculation is carried out in the slave without reference to the distributed clocks system. It is
therefore independent of the DC mode.
• In each cycle the interval between 2 positive edges of input A is counted with a resolution of 100 ns.
• If no edge change occurs for approx. 1.6 s, any period specification is cancelled.
