Guralp Systems CMG-DM24 - Manual (Page 81)

Operator's guide
Instructs the DM24 to begin writing new blocks to Flash memory as for
FILING, but also to transmit data to clients. Data is transmitted in
strict order, oldest first; the DM24 will only transmit the next block
when it receives an acknowledgement of the previous block. Once a
block is transmitted, it is marked as such in the Flash memory, and
may be overwritten later.
HEARTBEAT
Syntax: interval HEARTBEAT
When the DM24 is in FILING mode, it outputs status messages
periodically over the RS232 port (see Section 6.1, page 89). This
command changes how often these messages are produced.
If the digitizer has been configured to dial out over a modem link (see
+MODEM, above), it will dial out whenever it generates a heartbeat
message.
interval is normally measured in whole units of 30 milliseconds.
For example, issuing
600 HEARTBEAT
will cause the DM24 to output heartbeat messages every (600 × 30ms)
= 18,000 milliseconds = 18 seconds.
Alternatively, you can insert the word HOUR and specify interval in
hours:
5 HOUR HEARTBEAT
The maximum value allowed for HEARTBEAT is 300,000,000
milliseconds, which is 2,500 hours (approximately 100 days).
If you connect to a digitizer in FILING mode using Scream!, Scream!
will not detect the digitizer until it has sent a heartbeat message.
Therefore, you should use a relatively short heartbeat interval if you
have a continuously-connected instrument.
MS-GAP
Syntax: interval MS-GAP
The GCF protocol allows for transmitted data blocks to be
acknowledged by the receiver in order to improve the resilience of
links. Unacknowledged blocks can be re-transmitted immediately or
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