WR-ARP-ELAZ-100 and WR-RCU-100 Technical User’s Guide
14
Rev. F
9.2. Rotator Calibration
Calibration of the rotator is necessary, because the rotator does not have absolute
position sensors for azimuth and elevation. Instead, for each axis it has a sealed
Reed switch and a rotating magnet built into the gearbox assembly. For each full
rotation of the shaft in the gearbox, the switch is activated and this generates a pulse
which is detected by the rotator control unit. Each pulse represents a rotation of one
degree on the rotator shaft. The rotator control unit counts these pulses to determine
the angle traversed by the rotator.
For the rotator control unit to obtain the start and finish reference points (and hence
the full range of travel), it needs to turn the rotator until the limit (end-stop) switches
are activated. There are two limit switches incorporated per axis, one at the lower
end and one at the upper end of travel, these act as a built-in safety feature of the
rotator. As soon as a limit switch is activated, the power to the corresponding motor
will be disconnected and it automatically stops turning. Once a limit switch has been
activated, power to that motor must be reversed for it to rotate again.
Calibration needs to take place at least once during initial installation, but will also be
necessary under the following circumstances:
•
A rotator or rotator control unit is replaced with another one.
•
There is an unexpected interruption of power to the rotator control unit.
Normally, the calibration settings are stored in non-volatile memory by the
rotator control unit software whenever power is turned off by using the "soft"
On/Off switch on the front panel. These settings will then be used next time
the unit is powered on.
The calibration process is fully automatic and will be performed by the rotator control
unit application software whenever it detects that a calibration is required. However, it
may also be done manually at any time by the user, by selecting the Tools ...
Calibration function in the menu.
The following screen will be displayed when the Calibration function is activated:
Summary of Contents for WR-ARP-ELAZ-100
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