Guralp Systems CMG-DM16R8, Operating Manual

Page: 7 / 44

Operator's Guide
Front panel LEDs
Int Sync (Internal synchronization) : This LED flashes
GREEN whenever the digitizer's internal oscillator generates a
timing pulse. Should always flash as long as the digitizer is
powered.
Data (Data transmission) : This LED flashes YELLOW when a
GCF block is sent from the digitizer. The rate of flashing for this
LED depends on the configured sampling rate(s). No activity
indicates that data is not being sent.
Ack/Nack (Acknowledge/No Acknowledge) : Indicates
whether data blocks are being acknowledged by SCREAM
(requires duplex link, via serial port).
•
If LED is off, SCREAM is not attached, or the link to
SCREAM is simplex.
•
GREEN : SCREAM is attached and acknowledging blocks
(the LED blinks momentarily for each block received).
•
RED : a block(s) was not acknowledged.
ExtSync (External synchronization) : The timing pulse from
the GPS receiver.
•
No activity indicates that the GPS receiver is not attached
or is inoperative.
•
RED blink :- indicates GPS is attached and operating, but
has not yet obtained a fix.
•
GREEN blink : at one second intervals, indicates GPS has
obtained a fix.
•
GREEN blink synchronized with IntSync LED: indicates
GPS has obtained a fix and the internal oscillator is
synchronized to it.
2.2 Quick start
1. Connect the GPS cable to the digitizer’s plug marked
‘GPS Input’ (GPS is not essential for initial test setup).
2. Connect the cable from the plug marked ‘Data Output’ to
the COM port of a PC.
July 2016 7