Operator's guide
The DCM receives streams, but gaps appear in the data some
minutes after boot-up.
Check that the baud rate between the digitizer and the DCM is sufficient for all
the data streams you want to transmit. If it is not, the digitizer's output buffer
will gradually fill up until no more data can be stored. Increase the baud rate of
the digitizer through the DCM (or using Scream!), then set the baud rate of the
DCM's input port to the same value.
If you are using triggered output streams, be especially careful to allow a high
enough baud rate to transmit data from all possible output streams
simultaneously, or you will observe gaps when an event triggers the digitizer.
The DCM receives streams, but 2-minute gaps appear in the data
at 4-hour intervals.
After a reboot, the DCM takes around 2 minutes to begin transmitting. The
DCM runs a
guardian
process which monitors the health of the system. In
some circumstances
guardian
will need to reboot the DCM to attempt to
resolve a problem. If the reboot does not help, the DCM will soon find itself in
the same position, and
guardian
will reboot it again.
You can check the time since the last reboot with the command
uptime
, which
will respond with a line like
14:30:32 up 34 min, load average: 1.24, 1.32, 1.10
In this example, the DCM last rebooted 34 minutes ago.
The most common circumstance where
guardian
will reboot a DCM is when
the operator has instructed it to record data, but it cannot do so, either because
•
the Flash memory is full, and all connected USB disks are also full,
•
the Flash memory is full, and no USB disk is present; or
•
the Flash memory is full, and a USB disk is inaccessible for some other
reason (e.g. it is unformatted, incorrectly partitioned, or faulty).
December 2005
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