Maretron highly recommends using Maretron pressure transducers to achieve the specified accuracy; However, the FPM100 will support other linear 4-20mA transducers even though Maretron can't guarantee overall system accuracy.
The 4-20mA sensor must be a two wire loop powered 10-15VDC. If the chosen sensor has a primary power supply add a loop isolator between the FPM100 and the sensor.