Introduction
Cities around the world use road and street lighting for both safety and beautification purposes. One example of a type of road that can benefit from the beautification aspect is bridges, particularly since bridges are often visible for several miles. Bridge lighting can be used to accentuate a bridge's unique shape, and with the advent of reliable computers, dynamic lighting that exhibits complicated patterns can be used to attract attention and entertain passersby.

Until recently, bridge lighting was connected to RS-485 networks, which in turn connected to IPCs (Industrial PCs) located along the bridge. In this case, one or more multiport serial boards must be installed in each IPC. However, using IPCs for this kind of limited, special purpose application is nothing short of over kill.

Recently, a newer, more efficient and economical solution has become available. The "embedded computer," such as the UC-7400 series of embedded computers from MOXA, has all of the right features for controlling lights on a large bridge. For example, several hundred beautifying lights are installed on one of Shanghai’s bridges. The lights are controlled by several groups of light controllers connected to RS-485 networks. Special effects, such as running-train and flickering, are managed by a main controller. For this application, the main controller is required to have more than four RS-485 ports, and be suitable for installation in the light controller box under the bridge.

Previous Solution:
IPC (Industrial Personal Computer) plus multiport I/O cards:

New Solution:
MOXA Embedded Computer:

Advantages of the new solution:
1. Smaller size, space-efficient
2. Low power consumption
3. No fan, no hard disk, for higher reliability
4. Easy to program light controlling routines
5. CompactFlash slot for adding Gigabytes of storage space
6. Multiple connection options for greater networking versatility
7. Programmability gives system integrators infinite possibilities