Guralp Systems Limited
Breve Ocean Bottom Seismometer System

Chapter 4. Communicating with the OBS units

4.1 Connections

The first step is to connect the Deck Unit Communication Cable with the OBS unit(s). You will need to locate the 8-pin Aquamate connector dummy cap.

Unscrew the locking sleeve and remove the dummy cap to expose the 8 pin-out connectors. To connect the 8-pin Deck Unit Communication Cable to the Aquamate Connector, OBS align the connector pins with the socket pin inputs and careful push the connector into the socket. Once firmly in place, screw and hand-tighten the metal socket.

Connecting the Aquamate Connector to the Deck Unit Communication Cable.

On the left hand side of the Deck Control Unit, there are four 8-pin connectors. From left to right, these are classified as “Sensor 1” through to “Sensor 4”. Up to four OBS units can be connected simultaneously, which is ideal for pre-deployment huddle tests and to save time on deck during clock synchronisation. Each of these input connectors will be assigned a COM port number by the Deck Control Unit’s on board computer. These ports will be assigned numbers in the same order as the input numbers.

Deck control unit sensor inputs

To connect a OBS unit to the Deck Control Unit, align the connector pins with the socket pin inputs and careful push the connector into the socket. Once firmly in place, screw and hand-tighten the metal socket.

Connecting an OBS unit to the Deck Control Unit.

4.2 Powering-up the Deck Control Unit

The Deck Control Unit comprises a Microsoft Surface Pro computer. This computer is normally in ‘Sleep Mode’. Therefore, to enable the computer, push the switch beneath the ‘Power ON/OFF’ switch in the upwards direction.

Push the Computer on/off switch in the ‘up’ direction (in the direction of the orange labelled arrow) to enable the Tablet.

Login to the system using the user name “gsl” and password ‘”gsl”. The computer is touch screen and can be controlled using your finger or through the stylus attached inside the lid of the Deck Control Unit. To enter keyboard commands, a ‘Touch Keyboard’ can be enabled by selecting the keyboard icon located in the System Tray.

Important features located on the Desktop screen.

To enable the communications module of the Deck Control Unit, switch the ‘POWER ON / OFF’ switch to the ‘down’/ON direction. When switched on and the GPS successfully connected, the ‘PPS’ and ‘NMEA / SoH Rx LEDs will light green and flash red continuously.

4.3 Viewing waveform data

Launch the “Scream 4.5” program that is on the computer’s desktop screen. This will launch Scream’s main window which shows the four available COM ports. If everything is configured correctly, the connected OBS Unit’s Serial Number should show within one of these COM ports. Within this window, the streaming channels of the OBS unit can be seen: ****Z*, ****N*, ****E*, ****X* indicate the vertical, north, east components of the seismometer and the hydrophone, respectively. ****M* represent mass positions and ****0* are state-of-health streams.