Polarization: The feed turns clockwise (when looking through the antenna to the
satellite) for increasing values. When operated on the southern hemisphere, the
polarization sense must be set the other way round.
Motor driver type --- The ACU knows two different configuration modes to control a motor
driver. They are called DIR-START and DUAL-START. In DIR-START mode, the FWD signal
switches the motor on/off, the REV signal controls the motor direction. This is the
configuration many frequency inverters use. In DUAL-START mode, the FWD signal
switches the motor on in forward direction, REV activates the motor in reverse direction. This
configuration mode is convenient to control a motor with relays. Beside the modes DIR-
START and DUAL-START you may set the motor driver type to NONE which prevents the
ACU from controlling the motor at all.
Low speed threshold --- The ACU controls a motor at two speeds. If the actual position is
far away from the target value, the ACU commands the motor to use the fast speed. Once
the antenna comes close to the target value, the ACU slows down the motor. The low speed
threshold sets the angle deviation which lets the ACU use the fast motor speed.
Pointing hysteresis --- The ACU performs the motor control as a closed loop: if the angle
reading and the target value differ, the motor is switched on to compensate the difference. If
the difference is less than the hysteresis value, the ACU leaves the motor switched off. This
prevents the antenna from oscillating around the target value.
Motor timeout --- The ACU monitors the position readings while the motor is running. If
there is no change in the position readings for some time, the ACU assumes to motor to be
blocked and switches it off. This 'motor timeout' fault must be reset by the operator to
release it. A timeout value 0 disables the timeout.
Lower limit --- The minimum target value accepted at the user interface and via remote
control. This software limit prevents the ACU from running the antenna to the limit position
under normal conditions.
Upper limit --- The maximum target value accepted at the user interface and via remote
control. This software limit prevents the ACU from running the antenna to the limit position
under normal conditions.
Beacon Receiver
Beacon RX type --- Selects the source of the beacon level the ACU shall use. Available
options are sat-nms and VOLTAGE. In sat-nms mode the ACU reads the beacon level from
a sat-nms beacon receiver via UDP, in VOLTAGE mode the A/D converter input of the ACU is
read. Please mention, that in sat-nms mode, the beacon receiver must be set to send UDP
datagrams to the ACU/ODM.
Beacon RX IP address --- The IP address of the beacon receiver. Applicable only in sat-
nms mode.
Beacon RX voltage scale --- The scale factor for the analog beacon level input. The value
must match the scaling of the beacon level signal.
Beacon RX 0V level --- The beacon level which is displayed if the ACU recognizes 0V
beacon level input.
Location
GPS receiver type --- Defines the type of GPS receiver the ACU uses to read its geodetic
location.'NONE' tells the ACU that no GPS receiver is connected. The geodetic position of
the Antenna has to be entered manually. The ACU synchronized its internal clock to the
CMOS clock chip on the board.'NMEA' tells the ACU to expect messages from a NMEA GPS
receiver connected to the serial interface at CON8, pins 1-3. The ACU automatically sets the
antenna's geodetic location to the values received and synchronizes the clock to the GPS
(C) 2022, SatService GmbH
www.satnms.com
ACU2-19V2-UM-2209 Page 40/99
