The DDG is not only a replacement of your standard pneumo depth gauge but an diver depth tool with multiple extra features making the diver data registration more accurate and safe. The DDG has a standard built in depth sensor with a range of 0- 60 MSW. This sensor connected to the pneumo hose is used to measure the diver depth in the traditional way by pressurizing the pneumo hose until it is complete free of water.
Using the DDG in this way will not add much extra features as the diver depth reading is not constant and dependable on the manual pressurizing of the pneumo hose. For this reason the DDG is fitted with a connection for an external pressure sensor. This sensor is placed at the end of the diver umbilical at the diver end. The external depth sensor signal is transmitted to the surface using 2 wires in the diver umbilical cable.
Novasub has developed the UDS-3, a standard external depth sensor with a range of 0-60 MSW. The sensor signal is a digital signal over a milliamp signal. The external sensor is calibrated and has and accuracy better then 0,25% FS. By calibrating the external sensor, the DDG and the connection to the DDG do not need calibration.