BB-422LP9R

422LP9R-1712-1/2 B&B ELECTRONICS Model 422LP9R Port-Powered RS-232 to RS-422 Converter The 422LP9R is a port-powered two-channel RS-232 to RS-422 converter. It converts TD and RD RS-232 lines to balanced RS-422 signals. The unit is powered from the RS-232 handshake lines DTR and RTS. One of these handshake lines must be asserted (high) in order to power the unit (See Table 1). The RS-422 driver is enabled when RTS is asserted. Therefore, RTS must be asserted in order to transmit data. The RS-422 receiver is always enabled. If DTR is always asserted and the RTS is used to control the driver, the 422LP9R can be used as a RS-232 to RS-485 4wire converter. To insure reception, it is recommended that DTR is asserted. In order to maximize the amount of power available to the RS-422 driver, the RS-232 handshake lines are not looped back (tied together). As a result the following handshake lines will appear as disasserted (low): CTS, DCD, and DSR. Care should be taken to insure that any software being used doesn’t require any of these handshake lines be asserted. If existing software requires any of the handshake lines to be asserted, you can loop back the required handshake lines in your cable. Table 1 RTS State DTR State Low Low High High Low High Low High Functions Possible (when port powering unit) none Receive Transmit, Receive Transmit, Receive * NOTE: Low = disasserted and High = asserted Connections PRODUCT INFORMATION The 422LP9R can be connected in three different type of systems: RS-422 (Figure 1), four-wire RS-485 (Figure 1), and two-wire RS-485 (Figure 2). Regardless of the system, the 422LP9R must be connected with the proper polarity. With no data is being sent and the driver enabled, the RS-232 line should be negative and the TD(A) should be negative with respect to TD(B). Proper operation of any RS-422 system requires the presence of a signal return path between the signal grounds of the equipment at each end of an interconnection. This circuit reference may be established by a third conductor connecting the common leads of devices, or it may be provided by connections in each piece of equipment to an earth reference. When the circuit reference is provided by a third conductor, the connection between the signal grounds and the third conductor should contain some resistance (e.g. 100 ohms) to limit circulating currents when other ground connections are provided for safety. www.bb-elec.com orders@bb-elec.com support@bb-elec.com International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax 433-5104 European Office: Westlink Commercial Park Oranmore Co. Galway Ireland +353 91 792444 Fax +353 91 792445 B&B ELECTRONICS 422LP9R-1712-2/2 Table 2 - 422LP9R Pin Outs Signal DB-9S Pin # Transmit Data A (-) Transmit Data B (+) Receive Data A (-) Receive Data B (+) Signal Ground 8 3 2 7 4, 6 Biasing Resistors The biasing resistors for the RS-422/RS-485 receiver are 4.7K Ohm resistors. These resistors are labeled R1 and R6 (See Figure 3). Refer to B&B Electronics RS-422/485 Application Note for further information on biasing. Figure 3 Specifications Data Rate: Power: 115.2K Baud max. Port-Powered from RTS and DTR. Note: If external power is required, apply power to DTR (4) and SG (5). Source must supply greater than 6VDC and current limited to 40mA NOTE: When using an external supply, the supply should be connected only to specifically labeled power inputs (power jack, terminal block, etc.). Connecting an external power supply to the handshake lines may damage the unit. Contact technical support for more information on connecting an external power supply to the handshake lines. PRODUCT INFORMATION DECLARATION OF CONFORMITY Manufacturer’s Name: Manufacturer’s Address: B&B Electronics Manufacturing Company P.O. Box 1040 707 Dayton Road Ottawa, IL 61350 USA Model Numbers: 422LP9R Description: 9-Pin Port-Powered RS-422 Converter Type: Light industrial ITE equipment Application of Council Directive: 89/336/EEC Standards: EN 55022 EN 61000-6-1 EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11) Robert M. Paratore, Director of Engineering www.bb-elec.com orders@bb-elec.com support@bb-elec.com International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax 433-5104 European Office: Westlink Commercial Park Oranmore Co. Galway Ireland +353 91 792444 Fax +353 91 792445