ETS-Lindgren 2171B Boresight Antenna Tower - Manual (Page 51)

Operation | 51
T OWER E NCODER C ALIBRATION
Parameter C must be set to 2000 for the Model 2171B/2170B.
Parameter C, the encoder calibration parameter, is the setting that converts the
encoder count values returned from a motor base into the corresponding
centimeter or degree position reading. For towers, this represents the number of
encoder counts per meter. This parameter allows a variety of standard, retrofit,
and custom devices to be used.
If the given value does not work correctly, the encoder calibration value can be
determined using the following procedure:
1. Set the encoder calibration value to 1000.
2. Make sure the tower is positioned to allow at least one meter of travel in
the upward direction at an easily measurable height, and then set the
current position reading to 000.0. To allow this, you must adjust the lower
limit setting.
3. Use the STEP keys to adjust the height of the carrier until it is one meter
above the start point.
4. Record the reading of the display, ignoring the decimal point. For
example, 200.0 would be 2000. This is the encoder calibration value.
If the value is below 1000, the resolution of the encoder is low and the
Model 2090 will not provide 0.1-cm resolution, even though the display shows
that digit. If the value is past 9999, the encoder has too many counts per meter
and the controller cannot correct for it. In this case, contact ETS-Lindgren for
assistance.
5. Enter the encoder calibration value and reset the limits and position
information.
6. Test the tower by moving it a known distance and comparing the display
to the measured distance traveled. It may be necessary to adjust the
encoder calibration value up or down slightly depending on the result.
S TART -U P
After completing the pre-operational checks, turn on the Model 2090 by pressing
the power button.