(EQ2)
The first equation (EQ1) is implemented mechanically in the Trillium Compact through the
orientation of the individual axes. The second equation (EQ2) is implemented electronically
when the Trillium Compact is in XYZ mode.
Alternatively, seismic data can be digitized with the Trillium Compact seismometer in UVW
mode and the transformation to horizontal and vertical signals being implemented when the
data are processed. For example, UVW mode is particularly useful for the calibration of the
transfer function of individual axes.
To account for the source impedance, see
Table 10-1 "Ground motion response nominal
parameters for 120 s and 20 s models" on page 74
.
5.2 Serial RS-232 Communications
The 9600 baud serial communications interface is provided on the Rx and Tx signals of the
serial connector or the main connector, where DGND serves as the ground reference for the
serial link.
The Trillium Compact automatically senses when valid serial communication on the Rx line is
being received, and turns on the Tx line to transmit. The Rx and Tx signals share pins with the
CTRL and UVW control inputs. Care must be taken to ensure that the UVW/TX line is not being
simultaneously driven by the digitizer/data logger. When serial communications are occurring
on the Rx and Tx lines, the control line signals CTRL (or SP/LP) and UVW that share these pins
are not effective. For more details, see
"Digital Control Input Signals" on the next page
and
"Connectors and Cables" on page 79
Serial communication should not be active when the highest quality seismic signal is
desired because it may cause low levels of noise on the analog output signals.
Chapter 5 - Input & Output Signals
16889R10 • 2020-11-12
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