Guralp Systems CMG-3TD - Manual

CMG-3TD
Digital sensor
Installation
Check that you have all components and cables:
•CMG-3TD digital weak motion seismometer;
•GPS receiver;
•Brown GPS sensor cable;
•Blue/grey combined sensor PC and power cables;
•Sensor calibration data booklet.
You will need a Windows or Linux PC with an RS232
serial (COM) port and a 12–24 V DC power supply.
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Choose suitable sites to install the sensor and the GPS
receiver. The sensor should be mounted:
•at or, ideally, below ground level;
•in contact with bedrock or, if that is not possible, on
a hard granite or concrete pier;
•in an environment with constant temperature;
•shielded from air currents (e.g. in a polystyrene box);
•away from electrical cables and appliances.
The GPS should be placed:
•within 15 metres of the sensor;
•with a wide view of the sky and a low horizon.
Connect the various components together:
•Connect the brown cable from the GPS receiver to
the GPS connector on the sensor;
•Connect the 9-pin ‘D’ connector on the blue cable to
your PC’s serial (COM) connector;
•Connect the free, stripped end of the grey cable to
the power supply. Connect the black wire to the
negative (–) terminal and the red wire to the positive
(+) terminal;
•The blue and grey cables are joined together at a 10-
pin mil-spec socket. Attach this to the DATA
connector on the sensor. Do this step last.
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2
RS232
GPS
Power
supply
+ –
PC
CMG-3TD
3