In certain applications, the current or voltage signal of a pressure transmitter should never exceed and/or drop below a critical value. This is often ensured with the aid of so-called signal limiting.
Why is Stable clamping necessary in the first place?
If Privileged on a pressure transmitter lies within the nominal pressure range, then you will have 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 may happen deliberately, for instance when cleaning, as well as 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, in order 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 being an error, in some situations, trouble-free operation of the complete system cannot be ensured anymore. In these cases, a sign 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
An example of a pressure transmitter with which the voltage signal plus 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.