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Product description
2.3
Technology
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General description
Specifications
- Accuracy
- Internal resistances - Fuse
Default setting
General description
The functionality of the EL3681 is similar to that of a commercial digital multimeter. The terminal offers the
following features:
• Single-channel measurement
• AC/DC voltage measurement, range selection automatic through Autorange function or through the
controller; measuring ranges 300 mV, 3 V, 30 V, 300 V
• AC/DC current measurement in the 1 A path (internal fuse: 1.25 A) or 10 A path (no internal fuse),
measuring ranges: 100 mA, 1 A, 10 A
• Formation of measured values:
AC current/voltage is calculated as a true RMS value without DC component, an integration of the
signal waveform in the ADC takes place
DC current/voltage is calculated as an arithmetic mean value, an integration of the signal waveform in
the ADC takes place
• Electrical isolation from the fieldbus
• Very good interference immunity through dual-slope conversion technique
• Display of measurement type (current/voltage) and overload through LED
• Typical update rate approx. 2/s, after measuring range change up to approx. 1/s, with deactivated filter
approx. 16/s.
The data collection is shown in fig. Data flow EL3681.
Fig. 5: Data flow EL3681
Application note
For the measurement of a 60 Hz signal, the CoE (0x8000:0A [} 155]) object should be set accordingly. For all
other signal frequencies the 50 Hz preset is valid, because of the longer integration time. The accuracy
information shown below refer to a input signal of a frequency range of >0 .. 1 kHz. With higher frequencies
the measurement accuracy decreases (-3 dB > 500 kHz).
It is possible to measure a non-sinus AC input signal, if the Crest factor is < 3. The accuracy information
below refers to a Crest factor of max. 2.
The simultaneous electrical connection of both current paths (10, 1 A) and the voltage path for a following
alternating measurement of values is possible, but not recommended. In case of AC components in the
signal, a parasitic crosstalk from path to path can occur. After switching over, the process data update time
can be up to 1 second.
20
Version: 3.0
EL3681
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