Guralp Systems CMG-DM24 - Manual (Page 99)

Operator's guide
Because a trigger signal may last for only a short time, inserting
pins E and F directly into your equipment's power circuit is not
normally advisable. Ideally, the equipment should be
continuously powered and listening on dedicated trigger input
lines. If this is not possible, it may be enough to build a control
circuit with a time-out period, which supplies your equipment
with power for a suitable minimum length of time whenever
pins E and F are connected.
The digitizer cannot anticipate a trigger. Pre-trigger recording is
achieved using a continuously-updated buffer of the most recent
data. Any external equipment must have its own buffering
capabilities if you need pre-trigger data.
•
Connect pin B to pin E, and pin F to your equipment's trigger
signal input.
•
Connect the remaining pins as normal.
If your equipment needs a different voltage, you will need to provide a
separate voltage source for the triggering system. Be careful not to
connect two power supplies together. The instrument's power supply
can be protected by inserting a diode from pin B to pin E (see below).
Using an external trigger source
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