Testing In-Place Inclinometers before installation
1. Introduction
The
In-Place Inclinometer (IPI) utilises a string of MEMS tilt sensors each
mounted in a stainless steel housing and linked together by a rigid
gauge tube with universal joints at each end. This article explains how a simple test can be performed to
ensure functionality of an IPI string of sensors prior to installation.
Figure 1. Soil Instruments In-Place Inclinometer
2. Testing the output of the IPI
To
test the output of an IPI you will require a 10-16V DC and a
Voltmeter/Multimeter. Please connect the battery to the IPI to the
correct conductors shown in the following list. You will then
need to connect the Multimeter cables to the axis you require to check.
If your sensor is uni-axial there will only be the green and white
conductors, however if your sensors are bi-axial the cable will also
have blue and yellow conductors.
Conductor Colour - Identification
Red - Power+ (10-16VDC)
Black - Ground
White - A axis, Signal High
Green - Signal Low
Blue - B axis (bi-axial sensor), Signal High
Yellow - Signal Low
Bare Wire - Drain (Screen)
Warning:
Please ensure the IPI is wired in correctly to not affect the
polarisation. The IPIs do have reverse polarisation protection however
this will only last a certain amount of time.
Once
your IPI is fully connected please stand your IPI in a fully upright
position. Here the Multimeter should be reading zero volts. If you are
reading the A Axis the movement will be measured negatively in the
direction of the sprung wheel and positively in the direction of the
un-sprung wheel. The voltage output of the IPI is calibrated to +2.5V in
the positive direction and -2.5V in the negative direction, please note that you may receive a voltage reading to ±3V, however beyond ±2.5V we cannot guarantee the integrity of the results as this is outside of its calibrated range.
Figure 2. Tilt directions of the IPIs A axis
Measurements
on the B Axis, for bi-axial sensors will need to be made using the
yellow and blue conductors. Again the IPI will need to be in an upright
position with the sprung wheel pointing away from the user. As the user
begins to tilt the IPI left the output voltage will increase to +2.5V
and if this is then tilted right the user will see a negative output
voltage increasing to -2.5V.
Tip:
If the IPI is not stood in an upright position, such as if it is lying
on its side on a desk, you will not receive any voltage output from the
IPI.