Guralp Systems CMG-RTM User Manual

CMG-RTM
Real-time Clock/
GPS Emulator

Operator's Guide

Part No. MAN-RTM-0003

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 B 2015-04-15

CMG-RTM Real-time Clock / GPS Simulator

Table of Contents

1 Preliminary Notes..................................................................................................... 3

1.1 Proprietary Notice............................................................................................... 3

1.2 Warnings, Cautions and Notes........................................................................... 3

1.3 Manuals and Software........................................................................................3

2 Introduction............................................................................................................... 4

3 Operation................................................................................................................... 5

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

4.1 GPS Output, Power Input (right-hand connector)...........................................10

4.2 GPS Input (left-hand connector)......................................................................11

5 Specifications.......................................................................................................... 12

6 Revision history.......................................................................................................13

2 Issue B

Operator's Guide

1 Preliminary Notes

1.1 Proprietary Notice

The information in this document is proprietary to Güralp Systems
Limited and may be copied or distributed for educational and
academic purposes but may not be used commercially without
permission.

Whilst every effort is made to ensure the accuracy, completeness and
usefulness of the information in the document, neither Güralp
Systems Limited nor any employee assumes responsibility or is liable
for any incidental or consequential damages resulting from the use of
this document.

1.2 Warnings, Cautions and Notes

Warnings, cautions and notes are displayed and defined as follows:

1.3 Manuals and Software

All manuals and software referred to in this document are available
from the Güralp Systems website: www.guralp.com unless otherwise
stated.

April 2015 3

Warning: A black cross indicates a chance of injury or death
if the warning is not heeded.

Caution: A yellow triangle indicates a chance of damage to
or failure of the equipment if the caution is not heeded.

Note: A blue circle indicates indicates a procedural or
advisory note.

CMG-RTM Real-time Clock / GPS Simulator

2 Introduction

The CMG-RTM is a battery backed, high-precision, thermally­compensated, real-time clock module with simulated GPS output. It
obtains its initial synchronisation from a GPS receiver and, once
locked, starts generating NMEA sentences and a PPS (pulse per
second) signal, making it suitable for use as a time-source for GPS­synchronised equipment in situations where GPS receivers are
impractical. A large liquid crystal display provides status information.

z

Once the initial synchronisation source is removed, the CMG-RTM
continues to run under battery power, maintaining timing through the
use of a high-precision, thermally-compensated, crystal-controlled
oscillator. The CMG-RTM can then be transported to the deployment
site and connected to a digitiser, from which it subsequently draws
power. Once powered, it will generate the NMEA and PPS signals
which are required to synchronise the connected digitiser.

Each unit is individually factory-trained to calculate a temperature
compensation table with 0.1°C granularity, ensuring stability of
operation in a wide range of environments.

4 Issue B