Online systems
Most Nortek products can be used either in stand-alone or online mode. In stand-alone mode, data are collected to the internal recorder, and the power comes from internal or external batteries. For online system, data is transmitted to shore in such a way that the measurements are continuously available.
There are many types of online data collection but all share two fundamental characteristics:
- The data must be transferred to shore
- The instrument must have power in order to operate
There are several ways to transfer the data to shore. Conceptually, a cabled connection is simplest and Nortek has spent a significant effort to ensure that the cabled systems are both functional and reliable. The practical elements that are required for a cabled system are described here.
Acoustic modems is a good alternative in situations where cables cannot be used. Acoustic data transmission is a slow communication link and in the case of wave measurements it can only be used in conjunction with the ProLog wave processor. Also, acoustic modems require the instrument and modem batteries to replaced at regular intervals. More about acoustic modems here
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