Guralp Systems CMG-3T - Manual (Page 42)

CMG-3T
with OK. If there was a problem, such as one or more components
failing to unlock or centre, the controller will report NG (“no good”.)
L Lock
Sending L will start a lock sequence, as if you had activated the Lock
line on the output port (including unlocking the sensor before locking,
if necessary.) The sensor electronics will be placed in power saving
mode as soon as the masses are successfully locked.
If the locking process finishes normally, the controller will reply with
OK. If there was a problem, the controller will report NG.
C Centre
Sending C will start a centring sequence, as if you had activated the
Centre line on the output port. When the process finishes, the
controller will reply with OK, or NG if there was a problem. You may
need to issue the command several times before the masses are
adequately centred.
If you try to centre the masses when they are locked, the controller
will reply with OK immediately but take no action.
S Status
Sending S causes the controller to reply with the current
instantaneous mass positions, e.g.:
V: +5 N: +8 E: -10
The mass positions are measured by the controller's on-board ADC,
which has a nominal range of ±127 counts. For accurate mass position
information, you should use the analogue lines provided elsewhere on
the output connector.
Q Quit
Sending Q ends your command session, and puts the controller into
power-saving mode. To issue further commands, you will need to
wake up the controller by sending any character. This character will
not be treated as a command, and will not be echoed back to your
terminal.
5.4 The feedback system
The output from a modern broadband seismometer does not depend
on the natural characteristics of the instrument. Instead, the period
42 Issue N