Inside the DM24
7.4.4 Triggering several Güralp instruments simultaneously
A common use of the external triggering feature is to ensure that all instruments in
an array trigger at the same time. This can be achieved with the wiring layout below.
With this arrangement, any instrument can generate a trigger, which will be passed
on to all the instruments in the array.
For each instrument:
•
pin A is connected to a common ground;
•
pin B is connected to the instrument's power supply as normal and also to pin
E through a diode (an IN4001 is suitable);
•
pins F and H are connected to each other and to a common trigger line; and
•
the remaining data pins are connected to your recording equipment as
normal.
The diode at pin E is important, because if two instruments generate a trigger
simultaneously, their power supplies will both be connected via the internal relay
contacts to the common trigger line on pins H, and hence connected together. This
can cause considerable current flow with consequent risk of fire, as well as severe
damage to equipment and cables.
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Issue U - December, 2021
