Chesil Multi-Media Project
CMMP Instrumentation System
The CMMP instrumentation system uses an RS485 bus running at 19,200 bits/sec to link a number of intelligent sensors. The information from the sensors complies with the NMEA183 sentence standard. Most sensors return data in response to a query command to minimise bus collisions.
This bus connects all the sensors to a command/interface unit that controls the sensor interrogation and combines the data into a single stream. The command/interface unit also handles the controls for the audio and video systems.
The data is linked to the Chesil Visitors Centre via a fibre-optic cable carrying bi-directional data.
At the Visitors Centre the data is displayed on a PC and also stored on the PC hard disk every minute.
The instrumentation bus is also used to carry command and response information for the video and audio systems.
Sensors currently available |
||
| Wind speed/direction | Operational | Located on Black Hut, at end of useful life and replacement imminent |
| Air temperature | Operational | Located on Black Hut, due for replacement with more accurate unit |
| Beach light levels | Operational | Located on Black Hut. |
| Beach temperature | Operational | Located 0.5 metres into beach behind Black Hut |
| Light level | Operational | Located on Black Hut |
| Black body temperature | Operational | Gives a measure of the power from the sun |
| Rainfall | Operational | Located on Black Hut |
| Barometer | Operational | Located in Black Hut |
| Beach vertical temperature profile | Operational | Surface sensor has intermittent fault. Measures four temperatures up to 1 metre into beach |
| Water temperature | Operational | Located on intertidal camera (P2). Needs to be replaced with deeper sensor |