Beckhoff ELX3202, Руководство по эксплуатации

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Parameterization and programming
ELX3202 and ELX3204 45 Version: 1.4.0
Pt100: T < -200°C (R < 18 Ω): Index 0x60n0:01 [ } 61] and index 0x60n0:07 (under range and error bit) are
set. The smallest negative number is displayed (0x8001 corresponds to -32767
dec
).
For over range or under range the red error LED is switched on.
5.2.3.4 Notch filter
The ELX320x terminals are equipped with a digital filter. The filter performs a notch filter function and
determines the conversion time of the terminal. It is enabled via the index
0x80n0:06 [ } 53] and
parameterized via the index 0x8000:15 [ } 53] . The higher the filter frequency, the faster the conversion time.
Notch filter means that the filter has zeros (notches) in the frequency response at the specified filter
frequency and multiples thereof, i.e. it masks out these frequencies. In order to filter out 50 Hz, therefore, the
50 or the 10 Hz filter can be used. Since all frequencies lower than the notch frequency usually have to be
measured, however, the 50 Hz setting is to be used in this case.
Fig. 32: Typical frequency response of a notch filter set to 50 Hz
Note
Index 80n0:06
The filter function is always active even if the bit is not set, since this is obligatory for the
measurement process!
Details of the conversion time
• the conversion time depends on number of active channels, number of measurements (2/4-wire), filter
time, const. computing time
• the conversion time for the 2-wire measurement is about twice as long as for the 4-wire measurement
• the resistance measurement corresponds to a 4-wire measurement
• the process data TxPDO Toggle changes its state if a new measured value is present
Note
The filter characteristics are set via index 0x8000:15 [
}
53]
The filter frequencies are set for all channels of the ELX320x terminals centrally via index
0x8000:15 (channel 1). The corresponding indices 0x8010:15 of the ELX3202 or
0x8010:15, 0x8020:15, 0x8030:15 of the EXL3204 have no parameterization function.
Note
Switching off the unused channels of multi-channel terminals
Unused channels should be switched off if filter frequencies are ≥ 1 kHz (optimization of
conversion times)!
The channel concerned is completely disabled and the conversion time of the ELX320x is
correspondingly shortened.