Figure 1. Soil Instruments In-Place Inclinometer

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 knowledgebase article explains how a simple test can be performed to ensure functionality of an IPI string of sensors prior to installation.

2. Testing the output  of the IPI

To test the output of an IPI you will require a 10-16VDC and a Voltmeter/Multimeter. Please connect the battery to the IPI to the correct conductors shown in Figure 2. 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.

Figure 2. Conductors on an IPI

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 up right 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 3. 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.

If you have further questions relating to the above information please submit a ticket through the support site or call Soil Instruments on +44 01825 765044 for advice.

Checked MO'R v1.0 19/05/15