MAN-C24-0001 - Güralp Systems Limited
MAN-C24-0001 - Güralp Systems Limited
MAN-C24-0001 - Güralp Systems Limited
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CMG-CD24<br />
3. The values in the Level column are the number of counts above<br />
the baseline that channel must reach before a trigger is generated.<br />
The values are determined from the Details window for the<br />
channel under consideration. Note that the offset must be set to<br />
zero in order to determine the real baseline value.<br />
The Level values will be the same for each channel unless the<br />
“Common values” check-box is deselected.<br />
Once you have enabled the Level triggering method on a particular<br />
channel, you can use the Control window to change the level at which<br />
the system triggers without restarting the digitiser.<br />
3.1.3.3 External triggering<br />
When a digitiser or digital sensor triggers, it can send a notification<br />
signal to connected devices. You can configure other digitisers to<br />
respond to this signal by triggering in turn. This is an option which<br />
you can specify at the time of ordering.<br />
As an example, to instruct a stand-alone digitiser with digital trigger<br />
inputs to respond to trigger notifications generated by an attached<br />
digital sensor:<br />
1. Open the Configuration setup window for the digital sensor, and<br />
check Enable External Trigger Output to make it send trigger<br />
notifications to connected devices.<br />
2. UPLOAD the new configuration to the digital sensor.<br />
3. Open the Configuration setup window for the digitiser, and<br />
check Enable External Trigger Input to make it listen for<br />
notifications coming from the digital instrument and record data<br />
from its attached analogue instruments when it receives one<br />
(depending on its Output control configuration.)<br />
4. UPLOAD the new configuration to the digitiser,<br />
If a digitiser has both Enable External Trigger Output and Enable<br />
External Trigger Input selected, it will record data when it receives an<br />
external trigger notification as if it had triggered itself, but it will not<br />
send that trigger notification on to other digitisers. It will only send a<br />
trigger notification if its own triggering criteria are satisfied.<br />
3.1.3.4 Pre-trigger and post-trigger recording<br />
In order to capture all of a seismic event, it is often useful to be able to<br />
record data immediately preceding the trigger. <strong>Güralp</strong> digitisers have<br />
34 Issue C