Device Description - microHAM ARCO Manual

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1 - DEVICE DESCRIPTION

The ARCO is a modern rotator (motor + position sensor) controller designed for reliable
operation with virtually any rotator ever made as well as with the home brew rotators. It is a
completely self-contained stand alone rotator controller not requiring computer or any external
device or power supply for setup and operation, while providing a wide selection of interfaces for
remote control when necessary. It features several ways of controlling azimuth or elevation
heading using uncluttered graphical user interface on the 7" touch screen. Azimuth heading is
displayed on a great circle map, user centered to the rotator installation location, with four
different radius settings, live grey line projection, several coloring options and automatic
day/night color schemes. The controller supports Touch'n Turn feature, fastest possible heading
entry by simple touching desired direction on great circle map. Than classic tactile front panel
CW and CCW buttons, Point and Shot knob and heading entry keypad, either virtual on the
touch screen or hardware, connected to the USB host port on the ARCO.
Along with the manual control, ARCO offers rich connectivity for the computer using standard
RS-232 port, USB serial port not requiring any driver installation on Windows 10, macOS, and
Linux, and Ethernet port to enable control over Internet.
For rotator position feedback, ARCO supports wide range of the absolute and relative sensors
including rheostat, potentiometer, reed contact, Hall sensor, and PWM sensor. Additional digital
sensor port provides three differential lines supporting RS-485 communication as well as single
ended push-pull and open collector connection for various quadrature encoders. With high
resolution sensors positioning accuracy is 0.1º.
For the motor control, ARCO uses high current, 4-channel PWM driver with overload, short
circuit and overheat protections, combined with automatically operated, current monitoring
internal power supply, preventing driver damage caused by operation failures. This combination
is capable of driving safely any DC motor up to 48V or any AC motor up to 24V, including
innovative brake control reducing solenoid heat. Motor start and stop uses configurable, ultra-
fine gradual speeds ramps, significantly reducing inertial forces stress to the rotator, tower and
antennas, prolonging their lifetime. Gradual speed control uses auto-adapting procedure
considering variable, dynamically changing resistance caused by wind or ice.
ARCO uses built-in linear supply for silent, interference free continuous operation. Separate
built-in power supply for the motor is selectively controlled and entirely turned off when motor
does not turn, to avoid causing any possible interference to the sensitive receivers. For high
voltage or high power motors ARCO provides common control outputs for inverters as well as
industry standard MODBUS RTU control. All rotator settings including compensation for power
loss in the motor cables are menu driven, comfortably without requiring to open cover and
change some internal wiring.
Networking is another strong point of ARCO. ARCO supports not only LAN networking but
allows to build a simple but powerful, isolated two-wire local LINK bus, coupling multiple ARCO
controllers together for automated stacks tracking, multi-directional beaming, and counter
rotation for rotating towers. Unique feature of ARCO is a direct control of rotators connected to
another ARCO controllers, located either on the same LINK bus or anywhere in the world using
Internet connection. All this complex control is greatly simplified by using just two, easy to
handle SYNC and ALIGN buttons, and single ANTENNA button which allows to choose either
one of three antennas installed on the same rotator with different heading offsets, or any other
antenna present on the local LINK network through another ARCO, or on a remote LINK
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