Ultrasonic sensors / radar sensors

Ultrasonic or radar devices are available in screw or flanged fittings and attach to the top of a tank.


These devices transmit a signal pulse which is reflected back from the fluid surface to give a measurement of the distance to the liquid level. This measurement is converted into litres for the specific dimensions of the tank as set up in the HyDip device configuration.

Connecting to HyDip

  1. Remove the cover of the ultrasonic or radar sensor, and locate the connectors labelled 4…20mA. They should be labelled positive and negative. Insert a two-wire cable through the access port and attach it to these terminals.
  2. Connect the other end of the wire to a green 2-pin terminal block plug using the screw fittings.
  • Ensure the sensors are installed with the correct polarity; the plugs will only fit the sockets one way up.
  1. With the wires attached, simply plug the green terminal block plug into the appropriate socket on the HyDip (marked TK1 for sensor 1, TK2 for sensor 2 and so on).
  2. Take great care that the negative polarity of the gauge is connected to TK1- on the HyDip side panel, and the positive polarity to TK1+.

Please refer to the sensor manufacturer’s documentation for detailed specifications and installation instructions.

For EX rated sensors the connection may be slightly different, e.g. access may be gained by routing the wires through a side port. Refer to the gauge manufacturer’s documentation for detailed installation instructions.