Differential pressure transmitter uses two absolute pressure range transducers to measure pressure on the positive and negative side pressure ports and provide highly accurate pressure readings.

The PD-39X Differential pressure transmitter uses two absolute pressure range transducers to measure the pressure on the positive and negative side pressure ports. Digital compensation techniques are then employed to provide two highly accurate pressure readings via the built-in microprocessor. The two high precision pressure sensor measurements are subsequently subtracted by the digital electronics and converted into an analogue differential pressure signal output of 4-20mA or 0-10V DC.

The PD39X can withstand overpressures on either port of 1.5 to 3.3 times the maximum static line pressure without degrading the performance of the sensor.

Since there is no differential sensing diaphragm there is no need for mechanical protection stops to protect the sensor from accidental overpressure on one side.

This simpler mechanical design provides a very cost effective alternative to more conventional differential pressure transmitters.

The PD39X comes in five standard pressure ranges 3 bar, 10 bar, 25 bar, 100 bar and 300 bar differential.

Each range can be digitally turned down to the desired differential range.

It is recommended not to exceed a 20 to 1 turn down ratio in order to maintain a practical accuracy tolerance.

The accuracy of the PD-39X is typically 0.5% FS of the standard range which includes linearity, hysteresis, repeatability and thermal errors over a compensated temperature range of -10 to +80 deg C.

Any trade off in accuracy due to pressure range turndown will result in an improvement of overpressure, so both parameters should be considered in order to achieve the optimal differential pressure performance.

The PD-39X is fully programmable via a RS485 half duplex interface and you can configure the RS485 interface to readout the absolute pressures and temperatures of both sensors simultaneously with the analogue differential pressure output.

The RS485 communications also provides you with the ability to adjust zero and span settings at calibration intervals, set up special scaling for the analogue output, adjustment of the low pass filter damping, sample rate and bus addresses, and readout of product information such as range and serial number.

The analogue output can also be configured for flow measurements if you require a square root signal output.