Research Concepts RC2500 - Manual (Page 119)

112 RC2500 Antenna Controller Appendix K Driving 36VDC Motors
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA www.researchconcepts.com
Appendix K – Driving 36VDC Motors
Using the Smart Booster II
Single Speed 36 VDC AIU for an Antenna with TVRO-type Actuators
1.0 Scope
An antenna control package has been designed for Rincon Research. The customer has a pair of DH
4.2 meter antennas which utilize an elevation over azimuth type mount equipped with 36 VDC actuators.
The customer wants to modify the antenna to allow tracking of non-geosynchronous satellites based on
two line element data sets. The customer wants to send antenna steering commands to the antenna
controller from a PC.
To allow open loop satellite tracking the antenna needs to be equipped with true sensing position
encoders. The antenna controller will be an RC2500 running the Vertex 7134 outdoor unit software. The
RC2500 supports resolver type position sensors. For the AIU a pair of modified Research Concepts
Smart Booster II drives will be employed – one driving the azimuth axis and the other driving the elevation
axis. These are solid state drives with a maximum rated output of 8 amps at about 30 VDC. The drives
operate at a single speed and support dynamic braking and electronic over-current protection.
It is assumed that the antenna will use either the existing limit switches or will be equipped with limit
switches based on steering diodes. The modifications do not address polarization control.
This document describes the RC2500 interface to the AIU and the modifications performed to the Smart
Booster II product.
2.0 Smart Booster
The Smart Booster II is a 36 volt DC drive designed to allow satellite receivers with low current actuator
drives to control large satellite antennas equipped with 36 volt actuators. The Smart Booster II can
supply up to 8 amps (at 30 volts) to the actuators. The drive utilizes a single solid state H bridge with
built-in electronic overcurrent sensing and dynamic braking.
The Smart Booster II supports dual axis mounts – both axis can not be driven simultaneously, however.
A DPDT relay connects the H bridge to either the azimuth or elevation axis actuators. The input circuit for
each axis consists of a pair of opto-isolators. For a given axis, a pair of terminals connects the input
circuit to the low current actuator drive of a satellite receiver. When the Smart Booster detects current
flow it activates the H bridge and configures the DPDT relay if necessary. The polarity of the output
current is determined by the polarity of the input current.
For this application the following modifications are performed to the Smart Booster II …
The input circuits are modified to interface to the RC2500 control outputs. The RC2500 employs pull
down current drivers. The Booster is modified to accept a 24 volt DC loop power supply voltage
(available from the RC2500) as well as 3 pull down inputs to interface to the RC2500 AZ CW (EL UP), AZ
CCW (EL DOWN), and DRIVE ENABLE outputs. The DRIVE ENABLE output is used to reset a drive
alarm condition (caused by an over-current).
The DPDT relay is disabled to remove support for two axis control.
One of the motor drive terminals for the disabled axis is used to indicate drive alarm status.