Guralp Systems CMG-DM24 User Manual
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CMG-DM24
Instructs the DM24 to transmit current blocks to clients if possible, but
to store all unacknowledged blocks in the Flash memory and re-send
them, oldest first, when time allows. ADAPTIVE mode is best suited for
“real-time” installations where the link between digitizer and client is
intermittent or difficult of access.
If the communications link is only marginally faster than the data rate,
it will usually be busy transmitting real-time data. Thus, it may take a
while for the instrument to work through the missed blocks. In this
case, and if your client supports it, you may prefer to use the Block
Recovery Protocol to request missed blocks where possible (see
Some software packages (most commonly Earthworm) cannot handle
blocks being received out of time order. If you are using such a
package, ADAPTIVE mode will not work and may crash the software.
Buffering modes
There are two different buffering modes which affect how the internal
flash memory is utilized. Either may be used with any of the available
transmission modes.
RE-USE / RECYCLE
Command: RE-USE
Instructs the DM24 to carry on using the current transmission mode
when the Flash memory becomes full, overwriting the oldest data
held. This buffering mode is called RECYCLE in Scream! and on the
DCM.
For example, in DUAL mode with RECYCLE buffering, the latest
continuous data will be transmitted to you as normal, and the latest
triggered data may be retrieved from the Flash memory using Scream!
or the command line. However, if you do not download data regularly
from the Flash memory, you may lose older blocks. This mode thus
lets you define the end point of the data held by the instrument.
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