In certain applications, the current 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 sign clamping necessary to begin with?
If Big 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 that an originally planned pressure range is exceeded or is dropped below. This may happen deliberately, for instance when cleaning, together with accidentally, for instance through load variations or in case of a fault. In these cases, the sensor signal will also move beyond your defined limits, so that, for example, a current signal in the number 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 being an error, in a few situations, trouble-free operation of the complete system can’t be ensured anymore. In such cases, a sign limiting of the pressure transmitter makes sense, so that the output signal is maintained within the required range (e.g. 3.8 ? 21 mA).
Note
A good example of a pressure transmitter with that your voltage signal and also the current signal could be limited may be the model S-20 (for general industrial applications) or the model MH-3 (for mobile working machines) from WIKA.