In certain applications, the current or voltage signal of a pressure transmitter must not exceed and/or drop below a crucial value. This is often ensured using 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 instance when cleaning, and also accidentally, for example through load variations or in case of a fault. In such cases, the sensor signal will 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 that they recognise a signal outside of the defined limits being an error, in some situations, trouble-free operation of the entire system can’t be ensured anymore. In these cases, a signal limiting of the pressure transmitter is practical, so that the output signal is maintained within the required range (e.g. 3.8 ? digital pressure gauge ).
Note
A good example of a pressure transmitter with that your voltage signal and also 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.