BJ Marine Tech. was commissioned to design an instrumentation package for the Key Diving Company’s salvage digger.
The digger was originally designed as a manned submersible, powered from a mother ship via an umbilical cable.
As part of an upgrade program it was intended to provide instrumentation both for the operator and the mother ship. The instrumentation package was designed to be fitted into the operating cab, and be visible when the digger was manned as well as sending the data to the surface for remote operation. The data required was compass heading for the operating cab, position of the cab relative to the tracks. Pitch and roll data and depth. Additional data, leak detection battery voltage and temperature were also provided. The system was designed around the the BJMT Multiplexor and Switcher cards
The Multiplexer card unit accepts eight analogue inputs (0-5 Volt), sixteen digital inputs (on/off), sixteen digital outputs (on/off). and two serial channels. For this application the multiplexor was set as follows:
- Two of the analogue input channels were configured to read pressure sensors which monitored the external and internal pressures. The external pressure was scaled to give a depth reading.
- Other analogue inputs monitored the battery voltage and temperature inside the cab.
- Two of the digital inputs provided leak detection within the cab and main junction box.
- One of the serial channels read the Heading, Pitch and Roll data.
The analogue and digital data is multiplexed with the serial input data stream. This data stream is then transmitted to a host computer on the mother ship using the on board RS232, RS422, or TTL output options. And displayed in a clear and used friendly window on the control PC.
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