GCS Satellite Hardware Manual - Galaxy Control Systems

shield attached to ground at one end only. Keep the conduits as far away as reasonably
possible from all high power and/or high frequency lines. If there are any questions or doubts
concerning the running of wires, please contact Galaxy before proceeding. The maximum
distance between controllers is 1000 feet at 9600 Baud.
Line Drivers
Galaxy strongly recommends that Line Drivers be used when the network distance
between controllers is greater than 1000 feet, but less than 1.5 miles. Line Drivers are easy to
install and require no hardware changes to the controllers. Galaxy can supply Black Box’s
SHMB-2 Short Haul Modem. Other communication technologies such as fiber optics, laser and
radio frequency devices can also be used, however, Galaxy Control System’s Engineering Staff
should be consulted prior to installing these types of devices.
This diagram shows how the line drivers are connected in a one controller to one
controller setup. The data comes “OUT” of the primary controller, passes through the line
drivers and “IN” to the secondary controller. The data then completes the loop by passing
“OUT” of the secondary controller, back through the line drivers and then “IN” to the primary.
Figure 24
The second diagram shows the wiring configuration that would be used in a two
controller to two controller setup. In this diagram, the data passes “OUT” of the primary and “IN”
to the local secondary (second from the left). The data then travels “OUT” of the local or first
secondary and through the line drivers to the remote site. At the remote site, the data is
received “IN” by the second controller from the right. It then transmits the data “OUT” to the
farthest right controller. That controller then transmits the data through the line drivers and “IN”
to the primary controller. These examples should provide enough reference information when
designing the wiring for different numbers of controllers at each location.
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