The Fluke 750PA6 Absolute Pressure Module, 0 to 100 psi, 0 to 7 bar, 0 to 700 kPa is easy to use. To measure pressure, connect the pressure module to a pressure source or hand pump and then connect the pressure module cable to the calibrator. Apply pressure from the pressure source and it is displayed digitally on the calibrator. At the touch of a button, the pressure may be displayed in up to 11 different engineering units. When used with the 750 Series Documenting Process Calibrators, pressure readings can be date/time stamped and stored electronically for later retrieval. This saves time, eliminates errors, and supports compliance with quality standards and regulations.

The 750PA6 is highly accurate, with specifications that apply from 0° to 50°C (32° to 122°F), a feature that sets it apart from other pressure calibrators. This performance is possible through the innovative application of mathematics and micro-processing power. This series of pressure modules have silicon piezo resistor sensors which consist of a resistive bridge fabricated in a silicon diaphragm. Pressure applied to the diaphragm causes a change in the balance of the bridge which is proportional to the applied pressure. The bridge balance change is not linear and is very sensitive to temperature. However, since these effects are quite stable with time and with repetitive changes of condition, the sensors are carefully characterized.

During manufacture, Fluke's pressure module sensors are characterized by reading temperature and pressure at multiple points. A least-squares regression is used to calculate the coefficients of a polynomial expression for pressure. The coefficients, unique to that pressure module, are stored in the module's memory.

The 750PA6 has its own microprocessor, allowing it to run the measurement circuitry and communicate digitally with a calibrator. When connected to the calibrator, the module's coefficients are uploaded from the pressure module to the calibrator. Then, as pressure measurements are made, raw sensor values for pressure and temperature are digitally loaded to the calibrator, where the raw sensor values and coefficients are manipulated to derive and display the pressure reading.

Because of this innovative technique, digital communication eliminates errors due to poor connections and electrical interference. Secondly, the modules are inherently temperature-compensated from 0° to 50°C (32° to 122°F). Lastly, the modules are fully interchangeable, because all measurements are completed in the pressure module itself and then communicated to the calibrator in digitized form.

All modules, including the 750PA6, are calibrated independently of the calibrator, and can be used with any 740, 750 or compatible 720 or 710 series calibrator. Each module has its own serial number to maintain independent traceability.