Guralp Systems CMG-3T - Manual (Page 41)

Operator's guide
activating the CENTRE command again. You will probably need to
initiate the centring process several times before the masses are
adequately centred.
5.3 RS232 control interface
As an option, the 3T can be supplied with an RS232 control interface,
which uses three additional pins on the sensor output connector.
The control electronics save power by switching off the sensor
feedback electronics whilst the masses are locked. When you unlock
the masses, either using the standard logic lines (see above) or over the
RS232 interface, the control electronics automatically “wake up” the
rest of the sensor.
To connect to the RS232 control interface, attach the sensor to a PC's
serial port using the cable supplied, and use a terminal program such
as minicom (on Linux) or HyperTerminal (on Windows) to connect to
the port. Set the baud rate to 4800, with 8 data bits, no parity bit, 0
stop bits and no flow control.
Now power up the sensor. You should see the message PWR OK
indicating that it is ready to receive commands. Each command is a
single character. When you enter a command character, the controller
will echo it back to your terminal so you can see it.
After around 10 s of inactivity, the control electronics will go into
power-saving mode. You will need to wake up the controller by
sending any character before you can issue commands. This character
will not be interpreted as a command, and the controller will not echo
it back to your terminal.
H Help
Sending H causes the controller to reply with a short list of available
commands.
[U]nlock [C]entre [L]ock [S]tatus [Q]uit [H]elp
U Unlock
Sending U will start an unlock sequence, exactly as if you had
activated the Unlock line on the output port. The sensor will
automatically perform one round of centring after it has been
unlocked, and the electronics will be fully activated.
If the unlocking process finishes normally, the controller will reply
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