External Sensors

Here you will find external sensors which Nortek have integrated with Doppler instruments with an analog input (basically all but the Vectrino). Chances are that many other external sensors can be integrated via the analog input, but at the moment Nortek delivers the two mentioned here with our Doppler instruments.

Perhaps one of the most under utilized features of Nortek AWAC, Aquadopps, and Vector is the analog input. The analog input greatly extends the versatility of the instrument and effectively transforms the current meter/profiler into the multi-sensor device.

How it works

Nortek instruments have either one or two analog inputs. These have an operating range of 0-5 volts. Sensors that have an analog output in this range will produce a voltage that corresponds to the physical quantity it measures. The measured voltage is then recorded along with the current measurements.

The sampling on the analog channel can be configured to occur when the instrument measures current and/or waves. The configuration of this is done in the deployment planning of the instrument's software.

Typical Applications

  • Turbidity - Optical backscatter sensors.
  • Oxygen sensors.
  • CTD (conductivity, temperature, depth).
  • Monitoring voltage for other devices in the system.
  • Acoustic altitude sensor (distance from bottom) / Frame burial avoidance.
  • The sync line, which is not part of the analog lines, can be used to initialize external devices. This includes starting such devices as a GPRS modem, which generally requires 20-30 seconds to log onto a network.

Considerations

  • A special cable between the Nortek instrument and the analog sensor must be ordered.
  • Power can be supplied to the external sensor. This can be selected in the deployment planning, but estimates of "assumed duration" applies only to the Nortek instrument. Powering external sensors will reduce the duration by an unknown amount.
  • The Vector has high sampling rates of up to 64 Hz and can sample the analog line at the same rate.

 

Examples Below you will find some examples of sensors commonly used with the analog channel

Seabird MicroCAT 37 xm (160x160)Seabird MicroCAT This is the standard CTD sensor offered by Seabird. There are many different variants of this sensor, so make sure you choose the one that suits your needs: http://www.seabird.com/