NMEA data output refers to standardized text sentences used to transmit data between marine electronic devices, such as ADCPs. Nortek ADCPs can be configured to output NMEA data for integration with external systems.
First generation Aquadopps - both current meters and profilers - can be configured to output NMEA by starting measurements using the NM or NS command. These commands are described in the Integrators Guide. Note that it is not possible to store data to the internal recorder while outputting NMEA data.
When the instrument receives the NM or NS command, it responds with the number of seconds until the first NMEA message is output. This number equals the configured average interval. If the instrument responds with 0000 (which is NMEA's NackNack) it may indicate that the baud rate is too low to transmit NMEA messages, or that the configuration is incompatible with NMEA output. Also note that a continuous deployment plan cannot be used when enabling NMEA.
If you are unable to start the measurements:
- Ensure that there is enough time between the end of one measurement and the start of the next for the instrument to send the message.
- Reduce the number of cells to decrease the number of messages to be sent.
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