USB to RS-485 Optically Isolated Interface Handbook Revision 1.0

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Avis Montgomery
7 years ago
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1 USB to RS-485 Optically Isolated Interface Handbook Revision 1.0

2 Contents Overview... 1 RS-485 Connections... 1 Shield... 1 Line Term... 2 Bias 1 & Bias RS-485 Cable... 2 USB Installation... 3 Operation Important Note... 4 Firmware Update... 4

3 Overview The USB to RS-485 Optically Isolated Interface is designed to operate with the GSC range of RS-485 products. Unlike many USB to RS-485 converters, the provides electrical isolation of 1000 volts between the PC s USB connection and the RS-485 network. Electrical isolation of the RS-485 network is essential as these networks by their nature are usually long cables and can be subjected to high induced voltages which can damage the PC. Power for the is derived from the USB port and does not require an external power supply. The replaces the & in applications where the PC does not have a RS-232 port. The cannot be used as a RS-485 repeater and for these applications either the or should be used. RS-485 Connections The drawing below shows typical wiring of the RS-485 cable. USB to RS-485 Interface JP 2 & JP 3 Bias resistors ProxNet Jumpers - OFF This Line Termination Jumper must be ON! Only remove the jumper if the interface is NOT at the end of the RS-485 network Only connect the cable shield to SHIELD if not connected elsewhere on the network Other Products Jumpers - ON Connection to good quality Earth To RS-485 network Shield Earth The SHIELD connection is also the EARTH point for the isolated side of the interface. It is essential that an earth wire is run from this point to a good quality earth point (earth pin of mains plug). Cable Screen In principle the cable screen must only be earthed at one point in a network to avoid currents flowing in the shield that could induce interference into the cables. In ProxNet installations it is normal to connect the shield at the controller and so should not be connected at the USB to RS-485 optically Isolated Interface HANDBOOK Rev 1.0 Page 1 of 4

4 Line Term The Line Termination jumper must be ON if the is at the end of the RS-485 network. If it is not at the end of the network then the jumper must be OFF. Bias 1 & Bias 2 The Bias jumpers must both be OFF for ProxNet and on both ON for all other products unless otherwise advised. RS-485 Cable The RS-485 cable is connected to the GND, 485- and 485+ connections. To prevent the cable pulling out of the connector use a cable tie around the cable as a stopper USB to RS-485 optically Isolated Interface HANDBOOK Rev 1.0 Page 2 of 4

USB Installation The device driver for the 311-70 makes the USB port appear as a COM port and will require configuration after installation.

5 USB Installation The device driver for the makes the USB port appear as a COM port and will require configuration after installation. To install the driver, put the enclosed CD into the CDROM drive and then connect the using the provided USB cable. When prompted, allow Windows to search for the driver file. Once installation is complete it will be necessary to configure the associated COM port number and baud rate. Check the documentation of the GSC products before configuring the USB port. GSC products normally require COM port 1, 2 or 3 and a baud rate of 9600 or Open the Device Manager and expand the Ports (COM & LPT) which will display the USB COMM port as shown below. At installation, a random COM number is assigned to the port: Right click on the USB Communication Port and select properties and then click on the Port Settings Tab and set the baud rate as required by the application software. Then click in the Advanced button: USB to RS-485 optically Isolated Interface HANDBOOK Rev 1.0 Page 3 of 4

6 At the bottom of the Advanced Settings screen click on the COM Port Number drop down box and select a free COM port in the range 1 to 3. Make sure that you set the matching COM port number in the application software. Operation Important Note If the is disconnected from the USB port, the device driver will stop operating. Just reconnecting the will NOT restore communications. It is necessary to close the program that is communicating via the USB port and then restart the program. Firmware Update The unit has the facility to update the firmware. If this is required, the new firmware will be provided with instructions on the updating procedure USB to RS-485 optically Isolated Interface HANDBOOK Rev 1.0 Page 4 of 4

Communication with BushingGard using computer USB port

Communication with BushingGard using computer USB port There are two ways of communication with BushingGard through computer USB port: Direct communication between computer USB port and BushingGard USB