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 using so-called signal limiting.
Why is a sign clamping necessary in the first place?
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 can happen deliberately, for example when cleaning, as well as accidentally, for instance through load variations or in case of a fault. In these 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 can occur.
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 can’t be ensured anymore. In these cases, a signal limiting of the pressure transmitter is practical, so the output signal is maintained within the required range (e.g. 3.8 ? Centered ).
Note
A good example of a pressure transmitter with which the voltage signal and also 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.