This transducer is included in the Module package for your convenience. Transducers should have their temperature set to -10°C~50°C for reliable operation. When the supply voltage is 12V~24V, the transducers will operate well. The transducers can only function properly if the 4 pins are connected. It is important that the DC voltage be set to 24V to ensure that transducers are continuously capable of operating at the rated ambient temperature.