D
OCUMENT
301900,
R
EVISION
D
E
PI
S
ENSOR
U
SER
G
UIDE
29
Power Supply Options
The triaxial EpiSensor is offered in two power supply configurations; the
standard dual supply configuration and the optional single supply
configuration. The jumpers for these options are set at the factory and
should not be changed.
Caution
:
Damage to instrument
. When the EpiSensor is configured for
single-supply operation,
do not
connect any power source to pin H of the
connector. This pin is connected to the PGP (instrument case ground) which
connects to the EpiSensor’s case – if it is connected to pin H the power
source will be shorted.
Calibration Coil
Each EpiSensor module is equipped with a calibration coil. This coil is
isolated from other EpiSensor circuitry and accurately emulates the effect of
an acceleration on the system. This coil can be used to verify both the static
acceleration sensitivity of the EpiSensor and the dynamic response of the
system. When used with Altus recorders, the calibration signals are
automatically applied to the sensor. Access to the individual coils for
calibration verification is discussed below.
Calibration Coil Disconnect
X1, X2, and X3 are 2-pin headers that, when jumpers are installed, connect
the three calibration coils of the X, Y, and Z sensors to the CALDAC (or
STEP, as it is sometimes called) signal from the recorder. For test purposes,
these jumpers can be removed to allow direct access to the calibration coils.
For example, a spectrum analyzer or function generator’s noise output
can be connected directly to the calibration coil for transfer function
measurements. Normally, these jumpers must be installed in order to
allow recorders that can control the calibration coils to generate
functional test records.
Table 6: Calibration coil disconnect header
Header
Axis
X1
X
X2
Y
X3
Z
These headers are located on the bottom of the oscillator board.
