Guralp Systems CMG-40TDE User Manual

CMG-40TDE

Triaxi al seis mo me ter

Operator 's Guide

Part No. MAN-040-0004

Designed and manufactured by
Güralp Systems Limited
3 Midas House, Calleva Park
Aldermaston RG7 8EA
England

Proprietary Notice: The information in this manual is
proprietary to Güralp Systems Limited and may not be
copied or distributed outside the approved recipient's
organisation without the approval of Güralp Systems
Limited. Güralp Systems Limited shall not be liable for
technical or editorial errors or omissions made herein,
nor for incidental or consequential damages resulting
from the furnishing, performance, or usage of this
material.

Issue A 2012-08-31

Table of Contents

1 Introduction........................................................................................................................... 3

1.1 Connections....................................................................................................................6

1.1.1 DATA........................................................................................................................ 6

1.1.2 NET........................................................................................................................... 7

1.1.3 GPIO.......................................................................................................................... 7

1.1.4 USB........................................................................................................................... 7

1.1.5 GPS........................................................................................................................... 7

2 Getting started....................................................................................................................... 8

3 Understanding the manuals.................................................................................................9

4 Connector pin-outs.............................................................................................................. 10

4.1 DATA............................................................................................................................ 10

4.2 NET............................................................................................................................... 11

4.3 GPIO.............................................................................................................................. 12

4.4 USB............................................................................................................................... 13

4.5 GPS................................................................................................................................ 14

5 Revision history................................................................................................................... 15

Operator's Guide

1 Introducti on

The CMG-40TDE seismometer is a three-axis, broad-band, force­feedback seismometer packaged together with a 24-bit digitiser and a
flexible data acquisition and storage unit, all in a single sealed case.
The entire system is self- contained except for its power supply.

The 40T system combines low-noise components with high feedback
loop gain to provide a linear, precision transducer with a large
dynamic range.

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CMG-40TDE

The CMG-40TDE has a rugged, waterproof stainless steel design for
ease of installation. The lightweight sensor elements are designed so
that no mechanical clamping is required. Because of this, the 40T is
ready to record ground movements as soon as you provide it with
power. In addition, the sensor does not have to be levelled or centred
as long as the base is within 3 ° of horizontal. For the best results,
however, you should install where possible on a hard, near-horizontal
surface well coupled to the bedrock.

The CMG-40TDE consists of three internal modules, the 40T sensor, an
integrated digitiser and an integrated data acquisition system

4 Issue A

Operator's Guide

The integrated digitiser is a CMG-DM24, a low-noise, 24-bit ADC
module specifically designed for seismic data. The built-in digital
signal processor (DSP) provides simultaneous, multiple sample-rate
data streams at user-selectable rates. Up to 6 streams of data for each
component are available at sample rates from 1 to 1000 samples/s. A
precision microprocessor-controlled time-base synchronizes the
analogue-to-digital converters to the DSP and provides time-stamps for
data. A separate microprocessor system handles configuration and
sensor control, including mass centring and calibration.

The integrated data acquisition system is a CMG-EAM,
which provides serial and Ethernet communications, along with a
convenient web-based interface to all functions, including digitiser
and sensor configuration and control. It can act as a data recorder as
well as a protocol converter and communications controller. Based
around the powerful and stable Linux operating system, the CMG­EAM offers unrivalled flexibility, even including the ability to run
user-installed scripts.

Each instrument is delivered with a detailed calibration sheet showing
its serial number, measured frequency response in both the long
period and the short period sections of the seismic spectrum, sensor
DC calibration levels, and the transfer function in poles/zeros notation.

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