BB01 User Manual
to approximately -4.5 V when the ball reaches the other end of the beam. Sometimes when the
ball is sitting at the very end of the beam it may not be in contact with the sensor. In this case
the reading will initially be 0 V but when the ball begins moving the sensor signal will jump up
to about 4.5 V and then begin decreasing. Besides the ends of the beam, the signal should have
no discontinuities and little noise. Similarly for the SS01 sensor, the voltage signal should
decreasing from approximately 4.5 V to -4.5 V as the ball travels towards the end of the beam
with the analog connector.
Figure 21: Typical voltage signal from BB01 ball position sensor.
6.2.2. Troubleshooting
Follow the steps below if the potentiometer is not measuring correctly:
●
Verify that the power amplifier is functional. For example when using the Quanser UPM
device, is the red LED in the top-left corner lit? Recall that the analog sensor signal goes
through the UPM before going to the data-acquisition device. Therefore the UPM needs to be
turned on to read the potentiometer.
●
Check that the data-acquisition board is functional, e.g. the red LED on the Quanser Q4/Q8
terminal board should be bright red. If not then the DAC board fuse may be burnt and need
replacement.
●
Measure the voltage across the potentiometer. Ensure the potentiometer is powered with a
±
12V
at the 6-pin-mini DIN connector on the BB01, component #10 in shown in Figure 2, or on the
SS01, component # 14 in Figure 3. The two bottom pins of the DIN connector are GND pins
and the leftmost pin, i.e. where the green cable is connected to, outputs the voltage of the ball.
Using a voltmeter, connect one probe to the middle-left pin and the other to the bottom GND
pins. The voltage should vary between about
±
4.5 volts as the ball position is changed. If the
voltage does not change when you rotate the potentiometer shaft, your potentiometer needs to be
Document Number 709
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Revision 2.1
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Page 15
