User's Manual

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Figure 2.3 – T-bus Pinout Diagram
Providing System Surge Protection
The Wavetronix Click! 222 system surge protection devices are designed to prevent
electrical surges conducted along underground cables from damaging the cabinet
equipment.
The power and RS-485 serial connections on the T-BUS and faceplate are protected
from surges on the incoming wires of the sensor cable. The sensor cables are
connected via the terminal blocks on the PCU to the screw terminals on the bottom
side of the Click! 222. The screw terminals on the bottom side of the Click! 222
have circuitry that prevents impedance matching issues on long non-uniform cable
runs to the sensor installation sites.
The PWR and DC Surge OK LEDs indicate that the device is powered and that DC
surge protection is operational. The TD (transmit data) and RD (received data) LEDs
indicate when data is transmitted or received over the RS-485 T-bus, Bridge, C & D
ports. However, the TD and RD LEDs do not indicate data transmitted on RS485 A
or RS485 B. Furthermore, after an electrical surge there is no method to determine
if the RS-485 surge protection is still operational.
Note
The SmartSensor Matrix unit has built-in surge protection and there is not a
need to use a pole-mount box for surge protection. However, it is strongly
recommended that the sensor be connected to a surge protection device in the
main traffic cabinet. If you choose not to use surge protection in your main
traffic cabinet, please contact Wavetronix Technical Services for assistance.