| Below are photos and the schematic for the HexFet board. It can
be interfaced with the CT-1 controller to provide direct control of DC
motors. The supply voltage for the motors is applied to the board
and the outputs from the board connect to the motors. The board
has 4 channels, UP, DOWN, CW and CCW. There are inputs provided
for push button switches to manually control the motors, and there is
safety lockout circuitry on the board to prevent trying to activate both
directions at once. These Hex FET's can handle current up to 20
amps. In addition to motor control, the board also passes
through signals, from the CT-1 controller board, for A/D position
readout and motor speed control.
HEXFET board wiring
|
On the hexfet
board the motor connection is to the solder lug on each pair of
hexfets. Do not solder until you are sure of direction of
the motors or bring out to a strip so wires can be reversed.
The board is
the source of +13v (W1) Ground (W2) INPUT from POWER SUPPLY
voltage to run the controller via using the DIN8 plug and cable
you assemble.
The Din 8
cable is wired so that each pin 1 through 8 connects to the
corresponding pin 1-8 on the hexfet board.
Be sure to
FUSE each of the motor supply voltages into the board.
The hexfets switch on very hard (fast), much faster than a relay,
for example.
Motor supply
wiring:
AZ: Ground next to the R23, motor SUPPLY (+) is next to R24
EL: Ground next to W5, motor SUPPLY (+) is next to R3
Note: Motor
reversal will draw extremely high amperage if motor is still
turning when direction is reversed. This will be several
times more than the normal motor current. So you should
always allow motors to stop before reversing direction.
(When using manual switches, the controller will do this for you
automatically.) |
WIRING MANUAL SWITCHES
|
If you want to
have switch's installed to manual control the motors, use (con1)
or (con1A) for switch to ground, and we recommend to use three
position toggle switches, spring loaded, with center off. If
not you ** "WILL" forget ** and cause disaster at the antenna
and cables.
Use 2 of these
three position switches. One switch will be for CW and CCW,
and the other will be for Up and Down. |

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