Guralp Systems CMG-DM24 - Manual (Page 21)

Operator’s Guide DM-24 Digitiser
Issue G January 2003 19
3. DIGITISER CONFIGURATION AND
CONTROL MODE
A digitiser may be reprogrammed using the SCREAM configuration setup interface.
For any given digitiser, this interface module may be accessed by double-clicking with
the right mouse button on the digitisers icon in the Available Streams window. If you
single-click on the digitisers icon with the left mouse button, you must select Configure
from the pop-up menu. Using this module of SCREAM, you may interactively set the
digitisers system characteristics, control the output of streams at different digitisation
rates, turn on or off the output from the low digitisation rate multiplex channels (Mux
Channels), set output baud rates and digitiser buffering parameters, as well as invoke
seismometer calibration.
Using any standard terminal program such as Hyperterm or Kermit, these parameters
may also be changed by sending text commands to the digitiser. This mode may also be
invoked from SCREAM by single-clicking on the digitisers icon with the right mouse
button and selecting Terminal from the pop-up menu. When using standard terminal
programs, you must initiate command mode by typing Control-S when in the text
mode. This is done automatically by SCREAM when a terminal window is opened to a
digitiser. If you use the SCREAM configuration set-up interface, data collection will
continue while you are setting digitiser parameters. If you use SCREAM’s terminal
mode or another standard terminal program, data collection will be interrupted until you
exit terminal mode by issuing a re-boot command.
Parameters from most of the commands are stored to the battery-backed CMOS and
only take effect when the digitiser is rebooted. Some seismometer control commands,
such as unlocking and calibration take place immediately. When you click the
Download button from the digitiser configuration set-up interface, the parameters you
have chosen are transferred to the digitiser and it is automatically rebooted. You will
notice a data gap in the Waveview window corresponding to the digitiser you have
rebooted. This occurs because the reboot automatically clears the data buffer and resets
the output block counter.