Copyright © Sigicom AB 2019
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The use of US standard
ISEE Seismograph (S51 and S52)
Standards 51 and 52 can be used with or without trigger filter. If no
trigger filter is used, a transient will be recorded if a peak becomes larger
than the configured Trigger level, independent of the frequency. However,
when a trigger filter is selected, the actual trigger level depends on the
frequency of the peak, see Figure J1. There are two versions of trigger
filter; Drywall and Plaster, the only difference between them is their
nominal levels:
•
Drywall: 0.75 in/s
(4 – 15 Hz)
•
Plaster: 0.50 in/s
(2.65 – 10 Hz)
Figure J1. Trigger filter for S51 ISEE Seismograph.
The nominal level is defined in the frequency interval 4 – 15 Hz for Drywall,
and in the frequency interval 2.6 – 10 Hz for Plaster.
