Inside the DM24
7.4.2 Triggering your own equipment
If your equipment can trigger from 24 V DC, the simplest arrangement is to use the
voltage across the sensor's power supply as a trigger.
•
Connect the ground pin A to your equipment's trigger return line. If your
equipment does not have a separate trigger return line, consult its
documentation for how to apply trigger voltages. Güralp digitisers use the
power ground line as a trigger return. (The diagram above does not show the
power supply to either the sensor or the triggered equipment: only the
triggering system is shown).
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 digitiser 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.
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Issue U - December, 2021
