In certain applications, the existing or voltage signal of a pressure transmitter must not exceed and/or drop below a crucial value. This is often ensured with the aid of 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 precise 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 example when cleaning, in addition to accidentally, for example through load variations or in case of a fault. In these cases, the sensor signal may also move outside the 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 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 such 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 ? Judgmental ).
Note
An example of a pressure transmitter with that your 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.