D
OCUMENT
301900,
R
EVISION
D
10
E
PI
S
ENSOR
U
SER
G
UIDE
First, apply power to the system
without
connecting the cable to the
EpiSensor and then verify that the power connections are correct.
For a dual supply EpiSensor, verify that +12V is present on Pin J and –12V
is present on Pin H,
both referenced to power common Pin K.
For a single supply option, verify that +12V is present on Pin J referenced
to power common Pin K. Be sure that Pin H is not connected in this
configuration.
Caution
: Connecting incorrect voltages or wrong polarities ( >
"
15.75V )
will seriously damage your EpiSensor, as will making a connection to Pin H
in the single supply configuration.
Zero-Adjusting the EpiSensor
After the EpiSensor has been installed, leveled, and connected to the correct
power, measure the DC offset of each accelerometer. The DC offset should
be as close as possible to zero so that the recorded data has minimal offset.
With minimal offset the full range of the EpiSensor and recorder can be
utilized.
Methods of Measuring the DC Offset
If the EpiSensor is near the recorder, you may zero the accelerometers
by using the recorder as if it were a DVM. If you are using an Altus
recorder, use the AQ DVM command in QuickTalk's terminal mode.
If the EpiSensor is located at the end of a long cable, build a "break-out"
cable in order to access and measure voltages in each of the wires in the
EpiSensor cable. Be sure you are supplying the EpiSensor with
"
12 VDC
or +12 VDC for the single power supply option.
Performing the Zero Adjustment
Refer to Figure 9 to see the three access screws that, when removed, provide
access to the zero adjustment screws on the sensor modules.
Make the first zero-adjustment on the Z-axis accelerometer. Use one of the
methods described above to measure the sensor's zero output voltage.
Naturally, it is impossible to achieve zero offset. The table below will tell
you the ES-T acceptable range for DC offset for each possible
configuration. (If desired, smaller offsets can be achieved with some
patience.)
To zero balance the Z
-
axis:
1. Remove the zero balance access screw on the top of the
EpiSensor case.
