Polytec OFV-3001, User Manual

Page: 31 / 101

4-3
4 Making Measurements
4.1.3 Displaying the Output Signals
To display the output signals, proceed as follows:
Velocity
signal 1. Connect an oscilloscope to the BNC jack VELOCITY OUTPUT on the
front of the controller.
With a suitable selected measurement range, the expected signal form
should be visible at the VELOCITY OUTPUT.
2. Select the next highest measurement range if the L
ED
OVER is
continuously lit up at the front of the controller (refer to section 4.2.2 ).
Then the maximum velocity exceeds the full scale range. The display
may light up briefly while a different velocity measurement range is
being set or due to noise spikes.
3. Increase the intensity of the light scattered back by various surface
materials.
The noise level of the velocity output decreases. The minimum noise
level shows the optimal alignment and focusing for the surface quality
present.
Displacement
signal
(optional) 4. Connect an oscilloscope to the BNC jack DISPLACEMENT OUTPUT on
the front of the controller.
At the DISPLACEMENT OUTPUT, as a general rule the expected signal
form can not be seen initially.
5. Press the CLEAR key several times.
After pressing the key several times, the expected signal form should be
visible on the oscilloscope (refer to
section 4.2.3 , CLEAR function). If
not, then the displacement measurement range is unsuitable and should
be selected according to the information provided in
section 4.2.3 .
Sign
convention The following sign convention for direction applies to the output signals:
A movement towards the sensor head is considered as being positive. In
this case the velocity output voltage is positive and the displacement output
voltage is increasing.