RESEARCH CONCEPTS RC1500B Manual page 26

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RC1500B Single Axis Tracking Antenna Controller
1. Find the total resistance of the pot. See step (1) above.
2. Loosen up the allen screw which holds the shaft of the pot to the gear.
3. Apply power to the feed motor (as in step (3) above) to center the feed in the middle of its
range of travel. As the feed rotates, make sure that the shaft of the pot does not turn.
4. When the feed has been centered in its range of travel, connect the ohm meter between the
wiper and one of the other terminals of the pot. Rotate the shaft of the pot until the
resistance read from the ohm meter is one half of the value of the pot's total resistance
(obtained in step (1)).
5. Tighten the allen screw and verify that the pot is properly centered by performing the
procedure outlined earlier in this section.
3.3.3.2 Connecting the RC1500 to the Rotating Feed
To configure the RC1500 software to work with the RC2KPOL option the controller's 24 vdc
Rot Feed CONFIG mode item should be set to 1-Yes.
Figure 3.4 documents the interface of the RC1500 to the rotating feed. Two sets of electrical
connections are required to interface an RC1500 equipped with the RC2KPOL option to the
rotating feed device. Two conductors are required for the DC motor drive and a shielded triple
with bare drain wire is required to interface the potentiometer. The drain wire of the shielded
potentiometer cable should be tied to the Signal Return terminal, J4-1. The treatment of the
shield on the potentiometer interface cable is the same as for the antenna position sense lines –
see section 3.2.2
The RC2KPOL option can supply around 400 ma to the feed motor. 16 AWG or 18 AWG is
usually sufficient for the drive motor connections.
The potentiometer position sense interface wiring carries minimal current – 22 or 20 AWG
conductors are typically used to connect the controller to the potentiometer. Belden 8772 is a 3
conductor, shielded cable with a bare drain wire that can be used for the potentiometer
interface. Under no circumstances should a 5 conductor shielded cable be used to carry both
the motor current and the potentiometer position sense signals.
Figure 3.4 depicts the connection of a rotating feed device with the RC1500. Note that the
potentiometer interface cable's drain wire is connected to the Signal Return terminal (1) of
connector J4.
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Chapter 3 Installation/Setup
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