Guralp Systems CMG-3ESPCD User Manual
Page 72
CMG-3ESPCD Digital Broadband Seismometer
Command line interface
•
the current position of the read pointer,
•
the stream and time-stamp of the latest data in memory, and
•
the current position of the replay point.
The read pointer normally points to the oldest data in the file; however, if all
the data up to the replay point have already been downloaded, the read
pointer is set to the replay point and the number of blocks remaining unread
is updated. Downloads where a time-period is not specified always start from
the read pointer.
6.7.2 DIRECT
Syntax: DIRECT
Instructs the digitiser not to use Flash memory for storage. Instead, all data
are transmitted directly to clients. A temporary RAM buffer allows clients to
request blocks they fail to receive using the Block Recovery Protocol.
6.7.3 FILING
Syntax: FILING
Instructs the digitiser not to transmit blocks to clients, but to store all digitised
data in the Flash memory. The memory is used in circular fashion, i.e. if it
becomes full, incoming blocks begin overwriting the oldest in memory.
6.7.4 ADAPTIVE
Syntax: ADAPTIVE
Instructs the digitiser to transmit current blocks to clients if possible, but to
store all unacknowledged blocks in the Flash memory and resend them when
time allows. This differs from DIRECT in the following ways:
•
the client does not have to keep track of which blocks it has not
received, and
•
the entire Flash memory can be used for blocks awaiting
retransmission, rather than a temporary RAM buffer.
Adaptive mode is best suited for installations where the link between digitiser
and client is intermittent or difficult of access.
6.7.5 FIFO
Syntax: FIFO
Instructs the digitiser to begin writing blocks to Flash memory as for FILING,
but also to transmit data to clients. Data are transmitted in strict order, oldest
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Issue B - November 2013