Guralp Systems CMG-DCM build <10,000 User Manual
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Acquisition Modules and Platinum Firmware
Technical operation
15.1.1 Internal Connections
Internally, the digitiser module and acquisition module are connected using
three serial lines. The exact connections depend on the synchronisation
mode, determined by the service running on Port C of the acquisition module.
In all cases, the GCF data output from the digitiser module is connected to
Port A of the acquisition module, which should be set to “GCF in” at 38,400
Baud. It is currently possible to set the Baud rate of the digitiser's data output
port and of the EAM's Port A independently, leading to a loss of data
communication between the two modules if the two do not match. If you
wish to have a higher transfer rate between the two modules, both ends must
have their Baud rates increased separately.
The digitiser module also exposes a dedicated console connection, which is
internally attached to Port B of the acquisition module. This can be accessed
from the command line of the acquisition module or, if desired, made
accessible over the network. If you wish to disallow network access, set the
service on the EAM's Port B to “none”. To enable access over the network, set
the service on the EAM's Port B to “TCP serial converter. Serial data to TCP
link converter” and configure the converter according to the instructions in
It is currently possible to set the Baud rate of the digitiser's console port and of
the EAM's Port B independently, leading to a loss of data communication
between the two modules if the two do not match. If you wish to have a
higher transfer rate between the two modules, both ends must have their Baud
rates increased separately. The digitiser module's Baud rate must be changed
first.
Port C of the acquisition module is used for synchronisation and can either
provide NMEA to the digitiser module or share incoming GPS data from an
external receiver. Different internal connections are used in each case: an
analogue switch is controlled by the service selected for the EAM's Port C.
When the Port C service is set to “NMEA In”, the connections are as follows:
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Issue E - February 2014