Displacement Follower User’s Manual Version 1.4, April 19, 2004 IM1008
Page 16
Operating Procedures
General Operating Procedure
1
Prepare the target and lighting as specified. Note that the light source should be DC to eliminate the 120 Hz intensity
modulation, and that the light intensity should be uniform over the target area to be measured.
2
Connect the optical head to the control unit with the cable supplied.
3
Connect the control unit to a 117 VAC power source.
4
Estimate the maximum displacement you expect from the target during operations.
5
From the Standard Lens Set, and using the Lens Calibration data at the end of this manual, find a lens system that will
give a range of measurement comparable to the estimated maximum displacement for the target.
6
Attach the selected lens system onto the tracking head and place the tracking head at the proper working distance from
the target. Mount the head in a way that will minimize relative motion between the head and the target.
7
Observe the target through the viewer. If the target is approximately at the specified distance from the lenses, it should
be visible in the viewer. Adjust the head position until the target is in sharp focus. The full-scale measurement range of
the target is represented in the viewer by the 0.15” square. The system is capable of tracking a 20% target to
approximately 120% full scale, although linearity cannot be guaranteed beyond the normal full-scale limits.
8
Set the vertical and horizontal gain to the values specified in the System Calibration on page 22. The gain
potentiometer simply adjusts the proportionality between target displacement and output voltage. Note that this applies
to the fixed focus 105-mm lenses only. For variable-focus lens systems, the output gain will have to be determined by
actual calibration.
9
Set the output filter to
OFF
(widest bandwidth).
Figure 15a Figure 15b
10
Turn on the power. Allow for a 15-minute warm-up time.
11
Set the
Light/Operate
switch to
Light Level
. This causes the system to measure the amount of light coming from the
target area exactly in the center of the range of measurement.
12
Adjust the target position so that the small circle within the measurement range is totally within the dark area of the
target. See Figure 15a. Adjust the left-most lock-on control with a small screwdriver until the front panel meter reads –
20%.
