SmartSensor HD - Interprovincial Traffic Services

CHAPTER 5 • SENSOR SETTINGS 57SmartSensorConnectorPowerWiresTXRXCTSRTSRXTXRTSCTSRS-485WiresNull Modem CableDTE Device (PC)Figure 5.4 – RS-232 Connections˽˽In order to use hardware handshaking, the sensor’s RTS and CTS signals must beproperly connected. If the Flow Control option under the Serial and/or Modem Connectionscreens’ Advanced Settings is set to Hardware, you will not be able to connectif the sensor’s HW handshaking setting has been previously turned off. The reason youcannot connect is that the sensor’s RTS line is not asserted; as that line is connectedto the computer’s CTS line, the computer will not forward data messages it is given bySmartSensor Manager HD. To successfully connect, simply change the Flow Controlsetting in the Advanced Settings menu to None.Termination – Electronically turns communication bus termination on or off. This terminationapplies only to RS-485 ports. Only the end devices on a RS-485 bus shouldbe terminated. In general, the termination can be left in the default on position until amulti-drop bus becomes overloaded.