In certain applications, the current or voltage signal of a pressure transmitter must not exceed and/or drop below a crucial value. This can be 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 see a defined signal output (e.g. 4 ? 20 mA or 0 ? 10 V). However, in Report , 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 example through load variations or in the event of a fault. In Controlling , 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 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 makes sense, so the output signal is maintained within the required range (e.g. 3.8 ? 21 mA).
Note
A good example of a pressure transmitter with that your voltage signal as well as 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.