Research Concepts RC2500 - Manual (Page 175)

168 RC2500 Antenna Controller Appendix T Version 1.15 RC2500 Support on Special Features
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA www.researchconcepts.com
Appendix T – Version 1.15 Addendum
Support on the Special Features for the RC2500
This version of the RC2500 adds support for the following features …
Dual Speed Resolvers
Dual speed resolvers provide 720 degrees of indicated (or electrical) rotation for 360 degrees physical
rotation of the resolver input shaft. A conventional (or single speed) resolver produces 360 degrees of
electrical rotation for 360 degrees of mechanical rotation. Dual speed resolvers are sometimes also
referred to as four pole resolvers. Dual speed resolvers from Litton (Clifton Precision) are frequently
labeled ‘Brushless Resolver 2X’ with the 2X indicating dual speed.
Most Andrew APC 300 installations included dual speed resolvers on the az/el axis. In addition Andrew
also offered a polarization resolver kit where a single speed resolver was mechanically attached to the
rotating feed’s axis of rotation with 2:1 gearing. To the controller, a single speed polarization resolver
with 2:1 gearing is indistinguishable from a dual speed resolver attached directly to the polarization axis
of rotation.
The installer can configure the controller for dual speed resolvers via the Az Sensor, El Sensor, or Pl
Sensor CONFIG mode items. The menu items labeled ‘2:1’ specify dual speed resolvers. Those labeled
1:1 specify single speed resolvers. In these CONFIG mode items ‘FOR’ (Forward) and ‘REV’ (Reverse)
refer to the sense of reported resolver motion. If the resolver does not move in the correct direction,
switch from Forward to Reverse, or vice versa.
Starting with the version 1.15 software, the Reverse Az/El/Pol Sensor CONFIG mode items have been
replaced by the Az Sensor, El Sensor, and Pol Sensor CONFIG mode items documented below.
AGC Channel Display
The RC2500 requires an analog voltage proportional to signal strength to implement the Step Track
Algorithm. The controller accepts two channels of signal strength information, AGC 1 and AGC 2. AGC
refers to Automatic Gain Control. Receiver AGC circuits are frequently the source of signal strength
information supplied to the RC2500. Normally, the RC2500 uses the stronger of the two AGC input
channels for step tracking and the stronger of the two AGC inputs is displayed on the controller’s LCD (to
the right of the ‘S:’ banner).
When adjusting the Gain and Offset potentiometers of an AGC channel it is convenient to look at the
output of that channel rather than the peak value. In MANUAL mode, hitting the SCROLL UP or SCROLL
DOWN keys will display either the peak value (“S:876”), AGC 1 channel output (“1:423”), or AGC 2
channel output (“2:876”).
The current manual describes documents this feature but then has a disclaimer saying that this feature
has not been implemented.
Sticky Key Az/El Jog
During installation of the antenna or measurement of antenna patterns it is necessary to move the
antenna a lot. Some antennas move slowly and it is not convenient for installers to manually jog the
antenna over wide angles. With a sticky key jog operation the installer initiates antenna movement by
depressing the Az CCW, AZ CW, El Down, or El Up keys and stops antenna movement by hitting the
Stop key.
Sticky key jog operations occur from MANUAL mode. Sticky key jogs are disabled at program startup
and whenever the controller exits MANUAL mode. To enable sticky key jog operation the controller must
be configured for Expert Access. If Expert Access is enabled, to enable sticky key jog operation enter
50562 at the CONFIG mode Expert Access prompt. Control will switch to MANUAL mode and sticky key
operation is enabled. When a sticky key jog is in progress the controller still senses limits and detects
jammed errors. When the user exits MANUAL mode the sticky key jog feature will be disabled.
Replacing an Andrew APC 300 with a Research Concepts RC2500 Antenna Controller
Most Andrew APC 300 installations were equipped with dual speed az/el resolvers and single speed pol
resolvers with direct attachment (or 1:1 gearing) to the pol axis.
The following information was obtained from the APC300 antenna controller manual.