Guralp Systems CMG-CD24 - Manual (Page 77)

Operator's Guide
5.9.7 HEARTBEAT
Syntax: interval HEARTBEAT
When the CD24 is in FILING mode, it outputs status messages
periodically over the RS232 port. This command changes how often
these messages are produced.
interval is measured in units of 30 ms. For example, issuing
600 HEARTBEAT
will cause the CD24 to output heartbeat messages every (600 × 30) =
18000 ms = 18 s.
If you connect to a digitiser in FILING mode using Scream!, Scream!
will not detect the digitiser until it has sent a heartbeat message.
Therefore, you should use a relatively short heartbeat interval if you
have a continuously-connected digitiser.
5.9.8 MS-GAP
Syntax: interval MS-GAP
Sets the interval the digitiser should wait for a GCF ACK
(acknowledged) message, before assuming that the block could not be
transmitted.
If a period of interval passes without an acknowledgement, the
digitiser's behaviour depends on the current transmission mode (see
above.)
interval is measured in milliseconds. The default is 150. If the
value is greater than the average time between blocks being generated,
and an outage occurs in the return communications link, the digitiser
will be producing data faster than it can transmit them, and gaps will
start to be observed. However, systems using slower communications
links (e.g. radio links) may be unable to acknowledge blocks in under
150 ms. You should choose a value for interval which is suitable
for your particular installation.
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