In certain applications, the existing or voltage signal of a pressure transmitter should never exceed and/or drop below a critical value. This can be ensured with the aid of so-called signal limiting.
Why is a signal clamping necessary to begin with?
If the pressure on a pressure transmitter lies within the nominal pressure range, then you will see 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 example when cleaning, along with accidentally, for instance through load variations or in the event of a fault. In such cases, the sensor signal will also move outside the defined limits, so that, for example, an ongoing signal in the number of 3.6 to 25 mA may appear.
If now, however, the evaluation electronics are set so that they recognise a signal outside of 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 is practical, in order that the output signal is maintained within the mandatory range (e.g. 3.8 ? 21 mA).
Note
Limited of a pressure transmitter with that your voltage signal and also the current signal can be limited may be the model S-20 (for general industrial applications) or the model MH-3 (for mobile working machines) from WIKA.