User Manual Interface Converter
Contents
1. 1 e _ ___________ _ PC 2 A450 DTE DTE CES DB 25 Male A DB 25 Female 20 A450 User Manual 3 3 3 4 Using A450s as RS 232 Line Extenders A pair of A450s may be used to extend the distance at which RS 232 data is transmitted The A450s are connected via their RS 485 ports to take advantage of the greater data transfer distances available using RS 485 Recommended connection for two A450s together via their RS 485 ports A450 A450 Transient Protection Power surges or electrical transient voltages can be induced into cabling by such things as lightning strikes electric motors switches and the operation of heavy industrial equipment The use of long cables also increases the exposure to transient voltages A transient of sufficient magnitude can destroy an unprotected interface converter It is also possible for certain transients to pass though an unprotected interface converter and cause damage to the equipment which is attached By using High Speed Transient Voltage Suppressors on its communication lines the A450 absorbs much of the transient energy on these lines and helps clamp these surge voltages to a safe level This will ensure that both the A450 and any connected equipment are protected trom damage due to transients The A450 uses a Transient Voltage Suppressor Diode on each of the following e Transmitter pair TD and TD e Receiver pair RD and RD e Data pair Data2. LD DB 25 Male Shield RD 2 4 lt _ 3 TD PC Cable End TD 8 2 RD CTS 4 7 RTS RTS 5 8 CTS DTR 6 6 DSR E SG 7 5 SG DCD 8 3 gt 1 DCD DB 9 Female DSR 20 4 DTR A450 User Manual 8 0 SPECIFICATIONS RS 232C Port RS 485 Port Transient Protection LED Indicators Power Supply Dimensions Weight Operating Temperature Stroage Temperature Asynchronous RS 232D V 24 Select as DCE or DTE DB 25 female connector Speed capability dependant on cable length up to 115 2k bits per second RS 485 10 position Screw Terminal Block Switchable 1200hm Termination for 4 wire receiver Switchable 1200hm Termination for 2 wire receiver Transient Voltage Supression Diodes on RS 485 TD A and TD B RD A and RD B Surge capacity of 300 Watts per device at 1ms Response Time of less than 1ps Receive Data RS 485 Green Transmit Data RS 485 Green Transmit Enable Data RS 485 Yellow Accepts 9V 24V DC on input Supplied with 9V 200mA DC Power Adapter Reverse polarity protection Power screw terminal accepts wire range 14 24AWG 84mm x 58mm x 23mm 160 grams 10 to 35 C 0 to 45 C All specifications subject to change without notice 10
3. and Data Each diode has a response time of less than 1ps and power dissipation of 300 Watts for 1ms A450 User Manual 4 0 HARDWARE CONFIGURATION 4 1 4 2 RS 485 DIP Switch Settings In bus modes the RS 485 transmitter enable is controlled by the RS 232 handshake lines To enable the RS 485 transmitter both the CTS RTS and DTR DSR pairs must be asserted high Switch Settings ON O OFF Default Factory DIP Switch Settings 120ohm termination on 2 wire Bus RS485 receiver LEDs indicate RD TD Data Flow No Termination on RS 485 Receiver RS 485 Transmitter enabled when handshake lines are asserted RS 485 Receiver ALWAYS enabled 2 wire Bus with local echo DCE lt gt DTE Factory Default for the RS 232 Port is DCE i A450 User Manual 5 0 5 1 5 2 6 0 INTERFACE PORT PIN ASSIGNMENTS RS 232C Serial Port Pinout Pin Status Set for DCE Set for DTE 1 Used Frame Ground Frame Ground FG 2 Input Output RD TD 3 Output Input TD RD 4 Linked to Pin 5 CTS RTS 5 Linked to Pin 4 RTS CTS 6 Linked to Pin 20 DTR DSR 7 Used Signal Ground Signal Ground SG 8 Not used Pulled High 4K7 DCD DCD 20 Linked to Pin 6 DSR DTR RS 232 Interface Notes The RD signal must always be present even if it is not used by the attached RS 232 device Pins 4 5 6 8 and 20 are pulled to the correct levels to allow a PC serial port to operate under m
4. European Commissions EMC Directive 89 336 EEC We Name of Manufacturer ALFATRON PTY LTD of Address of Manufacturer UNIT 9 36 NEW ST RINGWOOD VIC 3134 AUSTRALIA Australian Company Number ABN 65 005 410 819 declare under sole responsibility that the product Product Name ASeries RS 232 to RS 485 Multi drop Interface Converter Model Number A450 to which this declaration relates is in conformity with the following standards CISPR 22 EN 55022 class B EMI from Information Technology Equipment ITE IEC 801 2 prEN55024 2 Electro Static Discharge Immunity IEC 801 3 prEN55024 3 Radiated RF Immunity IEC 801 4 prEN55024 4 Electrical Fast Transients Immunity N42 ALE TRA LOAM KADE 1 0 A450 User Manual PRODUCT DESCRIPTION An asynchronous RS 232 to RS 485 point to point or multi drop interface converter incorporating the following features e 2 wire and 4 wire RS 485 operation e RS 485 transmitter control with RS 232 handshake lines or dipswitch e 5 08mm spacing snap fit terminals for both data and power e DCE DTE switch selectable RS 232 uses DB25 connector e Transient Voltage Supression diodes used on RS 485 lines e Transmit data at up to 115 2Kbps e RS 485 range up to 1200 metres longer with low loss cable e RS 232 line powered RS 485 operation up to 100 metres using point to point or 9 12V DC power supply e RS 485 multi drop up to 32 driver and 32 receivers on 4 wire setup e Switchable termination resisto
5. User Manual ASeries A450 Interface Converter RS 232 RS 485 Multi drop ALFATRON the Interfacing Specialists A450 User Manual A450 User Manual Version 1 10 Copyright 2003 Alfatron Pty Ltd May 2003 DISCLAIMER Alfatron Pty Ltd has made every attempt to ensure that the information contained in this document is accurate and complete Alfatron makes no representation or warranties of merchantability or fitness for any particular purpose Alfatron reserves the right to make changes to this document at any time without notice Therefore Alfatron assumes no liability for damages incurred directly or indirectly from errors omissions or discrepancies with the hardware and the manual TRADEMARKS All Company and Product names are trademarks of the Company or Manufacturer respectively WARRANTY Alfatron warrants its products against defects in materials and workmanship for a period of one year from receipt by the customer All warranty is carried out on a return to depot basis unless an alternative warranty coverage has been arranged WARRANTY EXCLUSIONS The above warranty shall not apply to defects resulting from improper or inadequate maintenance by the customer unauthorised modifications or misues operation outside the environmental specifications for the product damage due to power surges lightening strikes or any other phenomenon outside normal operational specifications DECLARATION OF CONFORMITY according to the
6. d have a termination resistor at both ends of the bus e When DIP Switch position 6 is set to the ON position it engages a 120ohm resistor across Data and Data 3 2 3 21 3 22 A450 User Manual Using the RS 232 Port The RS 232 connection is switchable between DTE or DCE allowing the use of both straight though or crossed cables Straight Through RS 232 Cable To connect to a PC with a straight through serial cable sometimes called a modem cable choose DCE A typical straight through serial cable connects pins 1 2 3 4 5 6 7 8 20 on the DB 25 connector Power is drawn from CTS RTS and DTR DSR therefore it is necessary to connect these if the A450 is to be used in non powered mode In most applications it is necessary to connect all of the commonly used pins on the RS 232 port i e 1 2 3 4 5 6 7 8 and 20 on a DB 25 interface Crossed RS 232 Cable To connect to a PC with a crossed serial cable choose DTE A crossed cable is typically used to connect a PC to a Printer The following diagram shows a typical cable 4 PC 2 A450 DTE DTE CES DB 25 Male DB 25 Female 20 For reliable RS 232 line powered operation of the A450 use a cable with all pins connected as shown in the diagram above However the A450 internally ties CTS to RTS and DSR to DTR This means that the diagram below is a minimum cable configuration for unpowered operation
7. ost conditions without any additional loopback connections In the unpowered mode the power is scavanged from pins 4 5 6 and 20 Pins 4 5 6 and 20 are used to control the RS 485 transmitter enable when DIP Switch 1 is ON CABLE REQUIREMENTS Alfatron recommends the use of shielded cable with all of its products Shielding reduces EMI Radiation and improves noise immunity This helps minimise interference to other equipment and will improve communications reliability The recommended cable construction is as follows e Take the shield Surrounding cable wires and solder it to the Frame Ground FG pin If FG is not available use Signal Ground SG but in this case always use a separate wire for ground which is connected at both ends e The shield must be connected at both ends of the cable A450 User Manual 7 0 CABLE EXAMPLES 7 1 RS 485 Cable from A450 to User Device User Device JU UUL TD D A450 RD g JJ UO Q Z UO 7 2 RS 232 Connection to a PC with a DB 25 Serial Connector A450 Cable End DCE LD DB 25 Male ee FG 1 o 1 FG RD 2 _ 2 TD TD 3 gt 3 RD PC Cable End CTS 4 4 RTS DTE RTS 5 5 CTS DTR 6 gt 6 DSR Lee SG 7 7 SG DCD 8 8 DCD DB 25 Female DSR 20 cs 20 DTR 7 3 RS 232 Connection to a PC with a DB 9 Serial Connector A450 Cable End DCE
8. rs for RS 485 port e DIP switch selectable RS 485 local echo e RS 485 LED indicators for RD TD amp Transmit Enable g OO OO OO OO 0 a mge RS 485 Od A c 6 DIP Switch m DCE lt gt DTE Selection Slide Switch 1 1 RS 232 Port A450 User Manual 2 0 2 1 3 0 3 1 RS 232 Device INSTALLATION e Set DIP Switch settings to the requirement of the RS 485 target device e Select RS 232 port as either DCE or DTE as required LED indicators e LEDs will operate only if DIP Switch 4 is set to the ON position e RD LED will flash each time data is received by RS 485 Port e TD LED will flash each time data is sent by the RS 485 Port e TD Enable LED will illuminate when the RS 485 transmitter is enabled e These LEDs will not operate at any other time INTERFACE APPLICATION NOTES Using RS 485 in 2 wire bus mode e Simply connect the BUSa and the BUSb to the RS 485 2 wire bus positions Data and Data e When running a 2 wire RS 485 bus the RS 485 transmitter must be con trolled by the RS 232 serial device This transmitter may be controlled by either the RTS CTS or DTR DSR handshake pairs e If the RS 232 side is using software to control devices then it may require a local echo of what it transmits NIJINIZINIZINIJZING RS 485 Device RS 485 Device Set for DCE Example of a typical 2 wire setup GND sng e A long RS 485 2 wire bus shoul
Download Pdf Manuals
Related Search