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 with the aid of 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 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 example when cleaning, in addition to accidentally, for example through load variations or in case of a fault. In such cases, the sensor signal will also move beyond your 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 as an error, in a few situations, trouble-free operation of the entire system can’t be ensured anymore. In these cases, a sign limiting of the pressure transmitter is practical, so the output signal is maintained within the required range (e.g. 3.8 ? 21 mA).
Note
Coward of a pressure transmitter with that your voltage signal plus the current signal can be limited may be the model S-20 (for general industrial applications) or the model MH-3 (for mobile working machines) from WIKA.