Guralp Systems CMG-DM24 - Manual (Page 32)

Operator’s Guide DM-24 Digitiser
Issue G January 2003 30
AUXILIARY (MUX) CHANNELS
All the CMG-DM24 digitisers have as standard, five 16bit, 4 samples per second
channels. Three of these report the sensor mass positions, one is for inputting
calibration signals and the final one for reporting the internal temperature of the
digitiser.
In addition to these five channels, there are a further three channels available at the time
of manufacture for user specified options (pressure monitor, borehole orientation, etc).
Further to the above eight channels, there can be an additional eight 16bit auxiliary
channels which are standard on the stand-alone units, or can be ordered as an extra with
the digitiser modules. These can be used for the users own purposes, which can be
accessed as they require.
The additional eight channels are accessed via the Auxiliary port on the stand-alone
units, or, when ordered as an extra with the digitiser module, they are accessed via the
Analogue connector on the lid
Collection and transmission of the environmental channels is controlled using the Mux
Channels window. If a tick is placed in the box next to a channel, its data will be
collected and transmitted as a data stream in GCF format, just as with the normal data
channels. To indicate that the data comes from a Mux channel, the Stream ID will be
in the format ‘****Mn’, where M stands for Mux and n is a hexadecimal integer. The
integers between 0 and 15 are indicated by 0 - 9 and A - F, for 10 through 15. If a
Guralp seismometer is attached to the digitiser input (module or stand-alone), Mux
channels M8, M9 and MA will produce mass position for the vertical, north/south and
east/west components respectively. Channel ME monitors the internal temperature of
the digitiser.