User's Manual

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The other two serial connections provide dedicated communications to each sensor.
During real-time traffic operations with multiple sensors, one sensor will send
detection calls to a detector rack card over port A, and the other will send detection
calls to another detector rack card over port B.
On a 2-sensor or 4-sensor PCU, the sensor wired into the left most terminal block
will be connected to port A & C on the leftmost Click! 222. Port A is for detection
calls and port C is connected to the Command and Control Bridge. The sensor wired
to the next terminal block from the left will be wired to port B & D on the leftmost
Click! 222. Port B is for detection calls and port D is connected to the command
and control Bridge.
Similarly, on a 4-sensor PCU the sensor wired to the third terminal block from the
left will be wired to Port A & C on the right most Click! 222. And finally, the sensor
wired to the rightmost terminal block will be wired to Port B & D on the rightmost
Click! 222.
In other words, for detection calls the ports will be used in an ABAB pattern from left
to right on a 4-sensor PCU. Likewise, for the command and control Bridge, the ports
will be used in a CDCD pattern from left to right.
All these connections are surge protected when the protective earth ground is wired
to the PE terminal block on the back plate. Normally, the back plate should be
mounted to the chassis of the cabinet to provide a ground path. In addition it is
strongly recommended to provide a low impedance protective earth connection.
To provide a low impedance protective earth connection:
1. Connect a protective earth ground wire to the bottom-side of the PE block. A
10 AWG stranded wire is recommended for protective earth ground
connections. A 10 AWG wire is the largest that will fit in the terminal block.
2. Connect the protective earth ground wire to a protective earth screw
terminal within the main traffic cabinet.
Terminating the Sensor Cables
Note
When configuring the sensor, the configuration link of the install kit is rocked
onto the T-BUS, to the left of the gray T-bus connector. This connects the
configuration link to the Command and Control Bridge and allows for
convenient access to all sensors and rack cards from one connection point.
The configuration tool can automatically search for a list of all sensors or rack
cards on the bus.