Notch filter (conversion times), index 0x8000:06 / 0x8000:15

The EL3204-0162 terminal is equipped with a digital filter for each of the RTD channels and AI channels. The filters work as notch filters and determine the conversion time of the terminal. They are each parameterized via the index 0x8000:15 (RTD) or 0x8020:15 (AI). 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 Hz 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.

Index 0x80n00:06 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, filter time, const. computing time.
• The process data TxPDO Toggle changes its state if a new measured value is present.

The filter characteristics are set via index 0x8000:15 The filter frequencies are set for all RTD channels of the EL3204-0162 terminal centrally via index 0x8000:15 (channel 1 RTD).

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 EL3204-0162 is correspondingly shortened. By double-clicking on the corresponding object 0x8000:1A/ 0x8010:1A the corresponding channels can be switched off in the Set Value dialog by selecting the "Enum" value "not connected". The settings "3-wire" and "4-wire" are present for compatibility reasons and have no function. (see Fig.: Set Value dialog)