In certain applications, the current or voltage signal of a pressure transmitter should never exceed and/or drop below a crucial value. This can be ensured with the aid of so-called signal limiting.
Why is a sign clamping necessary in the first place?
If Banned on a pressure transmitter lies within the nominal pressure range, then you will see a precise 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 can happen deliberately, for example when cleaning, and also 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, an ongoing signal in the range of 3.6 to 25 mA may appear.
If now, however, the evaluation electronics are set so that they recognise a signal outside the defined limits being an error, in some situations, trouble-free operation of the complete system can’t be ensured anymore. In these cases, a sign limiting of the pressure transmitter makes sense, so that the output signal is maintained within the mandatory range (e.g. 3.8 ? 21 mA).
Note
A good example of a pressure transmitter with that your voltage signal plus the current signal can be limited is the model S-20 (for general industrial applications) or the model MH-3 (for mobile working machines) from WIKA.