DI/DU Piezo and capacitance sensors
Rugged industrial pressure measurement
The DI/DU series utilize either a Piezo sensor, or a miniaturized capacitance cell. This enables measurement from 2000 to 1mbar (1500 to 0.75 torr) for the Piezo based vacuum sensors and 200 to 0.1 mbar (150 to 0.075torr) for the capacitive based vacuum sensors.
Whatever sensor type that you use, there is a choice of FPM or EDPM sealing to make sure that you use a sealing technology ensuring the longest life in your process. The final decision point is whether you want a 0-10 V analogue output (DU series) or a 4-20mA output (DI series). 4-20mA outputs are typically used when there is a risk of electrical interference, or a risk of signal drop over long cables.
We also offer differential Piezo sensors (-1000 to +1000mbar) enabling measurement of pressure relative to atmospheric pressure, useful for when monitoring load lock style chambers.
User advantages
Piezo vs. capacitive diaphragm measurement
The difference between a Piezo and capacitive diaphragm measurement is that in capacitive gauges the deflection of the diaphragm is measured electrically rather than mechanically. Therefore, capacitance gauges react much quicker and are more precise for accurate measurements at lower pressures.
The piezo-resistive membrane sensor uses a ceramic sensor. Under pressure a thin membrane on the back of which a resistance measuring bridge is applied. The resulting upset of the measuring bridge is a measure of the absolute pressure acting of the membrane. This method of measurement is more cost effective than capacitance sensing, and is therefore used in cost sensitive situations, such as food and packaging.
The DI/DU range is typically used in harsh processes, in dirty environments. Because of this, all variants are IP54 rated and are able to operate in temperatures from 0 to 60C, meaning they are perfect for use in unprotected environments typically found in heavy/general industry. Another common feature across the DI/DU series is their compact size, making them suitable for integration into tight spaces inside equipment.
Whilst these gauges are typically integrated directly into a PLC, especially when looking at 4-20mA outputs if you require a local display they can be integrated via our DISPLAY or GRAPHIX series controllers. This enables you to monitor multiple pressure points at a single point in your system.
