Évaluations - 1, GPA: 5 ( )

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Or, again, you can constantly enable the RS-422/485 driver by setting the W15 jumper to the B and C position. Data going from the RS-422/485 interface to the RS-232 interface: When the RS-232 interface is configured as DCE, data received on the RXA and RXB pins of the RS-422/485 port will be transmitted out Pin 3 (RD) of the RS-232 interface. When the RS-232 interface is configured as DTE, data received on RXA and RXB pins of the RS-422/485 interface will be sent out Pin 2 (TD) of the RS-232 interface. For more on the Converter’s RS-232 pinning, see the Appendix. 11 RS-232-RS-422/485 CONVERTER (DATA ONLY) RS-232 side RS-422/485 side Figure 5-1. Block diagram of Converter functions in DCE mode. RS-232 side RS-422/485 side Figure 5-2. Block diagram of Converter functions in DTE mode. 12 CHAPTER 5: Operation 5.2 RS-422/485 Circuitry The RS-422/485 side of the Converter is made up of the driver, receiver, and line- termination networks. As described in Chapter 3, you can use switch S2 to either connect the receiver’s termination network to the line (terminate the RS-422/485 port) or leave it unconnected (unterminated). Having the line terminated will reduce distortion and improve the overall signal quality in most applications. For point-to-point systems where only two devices are connected to the line, each device should have the termination network connected to the line. In multipoint applications, only the two devices at the extreme ends of the line should have the termination network connected to the line. If any of the other converters were configured as “terminated,” the amount of signal distortion would increase and probably cause errors in the data being transmitted. For more on the RS-422/485 connector pinning, see the Appendix. 13 RS-232-RS-422/485 CONVERTER (DATA ONLY) 6. Troubleshooting 6.1 Calling Black Box If you determine that your RS-232-RS-422/485 Converter (Data Only) is malfunctioning, do not attempt to alter or repair the unit. It has no user-serviceable components. Contact Black Box Technical Support at 724-746-5500. Before you do, make a record of the history of the problem. We will be able to provide more efficient and accurate assistance if you have a complete description, including: • the nature and duration of the problem; • when the problem occurs; • the components involved in the problem; • any particular application that, when used, appears to create the problem or make it worse; and • the results of any testing you’ve already done. 6.2 Shipping and Packaging If you need to transport or ship your Converter: • Package it carefully. We recommend that you use the original container. • If you are returning the unit, include everything you received with it. Before you ship the unit back to Black Box for repair or return, contact us to get a Return Authorization (RA) number. 14 APPENDIX: Pinouts Appendix: Pinouts Table A-1. Pinning of the RS-232 connector (DB25 female). Pin Number and Signal Function Pin1 — Frame Ground Connects the Converter’s frame ground to the frame ground of the RS-232 device. Pin 2 — TD When the Converter is set to DCE, data is received on Pin 2 and the TX LED lights up when Pin 2 is a “space” (logical zero). When the Converter is set for DTE, data is output on Pin 2, in which case the RX LED lights up when Pin 2 is a “space.” Pin 3 — RD When the Converter is set for DCE, data is output on Pin 3. The RX LED lights up when Pin 3 is a “space.” When the converter is set for DTE, data is received on Pin 3 and the TX LED lights up when Pin 3 is a “space.” Pin 4 — RTS When the Converter is set for DCE, RTS is an input which turns on the RS-422/485 driver when true. When the Converter is set for DTE, RTS is always an output and is always true. (In DTE mode, CD controls the RS-422/485 driver.) Pin 5 — CTS When the Converter is set for DCE, CTS is an output that follows the RTS/DTR input. When the converter is set for DTE, CTS is not used. Pin 6 — DSR When the Converter is set for DCE, DSR is true. When the Converter is set for DTE, DSR is not used. Pin 7 — Signal Ground Connects the signal ground of the Converter to the signal ground of the RS-232 device. Pin 8 — CD When the Converter is configured DCE, CD is always true (and RTS controls the RS-422/485 driver). When the Converter is set for DTE, CD is an input which turns on the RS-422/485 driver when true. Pin 20 — DTR When the Converter is set for DTE, Pin 20 is true. 15 RS-232-RS-422/485 CONVERTER (DATA ONLY) Table A-2. Pinning of the RS-422/485 connector (4-position terminal block). Pin/Signal Function TXA and TXB Data received by the Converter from the RS-232 port is transmitted out of the unit over twisted-pair wires using these two outputs. The “TX” LED indicates the state of these two leads. When the TXA lead is positive with respect to the TXB lead (a zero is being transmitted), the “TX” LED is lit. RXA and RXB These are the received data inputs for the RS-422/485 port. The status of these leads is monitored by th...

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