In certain applications, the current or voltage signal of a pressure transmitter should never exceed and/or drop below a crucial value. This could be ensured with the aid of so-called signal limiting.
Why is a signal clamping necessary in the first place?
If the pressure on a pressure transmitter lies within the nominal pressure range, then you will have a defined signal output (e.g. 4 ? 20 mA or 0 ? 10 V). However, in technical applications, it frequently happens an originally planned pressure range is exceeded or is dropped below. This may happen deliberately, for instance when cleaning, and accidentally, for instance through load variations or in case of a fault. In such cases, the sensor signal may also move outside the defined limits, in order that, for example, a current signal in the range of 3.6 to 25 mA may appear.
If now, however, the evaluation electronics are set so they recognise a signal outside the defined limits as an error, in some situations, trouble-free operation of the complete system can’t be ensured anymore. In these cases, a signal limiting of the pressure transmitter makes sense, so the output signal is maintained within the mandatory range (e.g. 3.8 ? 21 mA).
Note
เกจวัดแรงดัน of a pressure transmitter with which the voltage signal as well as the current signal could be limited is the model S-20 (for general industrial applications) or the model MH-3 (for mobile working machines) from WIKA.