MODEL USB-COM-2SM USER MANUAL
Contents
1. Address Map The core of the UART function is supplied by the FTDI FT232BM chip Chapter 6 Connector Pin Assignments DB 9 Male Pin for RS 232 Signals RS 485 Signals RS 422 Signals each of Ch A G Industry Standard Also 4wire RS485 Ch x 1 DCD Chx 2 RX TX RX Chx 3 TX Ch x 4 DTR Chx 5 Gnd SR Chx 7 RTS Chx 8 CTS me3 8 Bene Table 6 1 Serial Connector Pin Assignments Appendix A Application Considerations Introduction Working with RS422 and RS485 devices is not much different from working with standard RS232 serial devices and these two standards overcome deficiencies in the RS232 standard First the cable length between two RS232 devices must be short less than 50 feet at 9600 baud Second many RS232 errors are the result of noise induced on the cables The RS422 standard permits cable lengths up to 5000 feet and because it operates in the differential mode it is more immune to induced noise Connections between two RS422 devices with CTS ignored should be as follows Device 1 Device 2 Table A 1 Connections Between Two RS422 Devices A third deficiency of RS232 is that more than two devices cannot share the same cable This is also true for RS422 but RS485 offers all the benefits of RS422 plus allows up to 32 devices to share the same twisted pairs An exception to the foregoing is that multiple RS422 devices can share a single cable if only one will talk and the others will all rece2. for your software format and operating system Substitute the appropriate drive letter for your CD ROM or disk drive where you see d in the examples below WIN95 98 Me NT 2000 XP 2003 a Place the CD into your CD ROM drive b The CD should automatically run the install program If the install program does not click START RUN and type AJANTA click OK or press Ed C Follow the on screen prompts to install the software for this board LINUX 1 Please refer to linux htm on the CD ROM for information on installing under linux Hardware Installation The unit can be connected to any USB 2 0 or USB 1 1 port Please install the software package before plugging the hardware into the system Chapter 3 Option Selection Refer to the setup programs on the CD provided with the board Also refer to the Block diagram and the Option Selection Map when reading this section of the manual Terminations A transmission line should be terminated at the receiving end in its characteristic impedance Installing a jumper at the locations labeled RS485 LD applies a 1200 load across the transmit receive input output for RS485 operation Jumpers having to do with the termination of each channel are located near the output connector They are labeled by channel The load jumper is labeled TERM The other two jumpers are used to connect the transmit and receive lines for the two wire RS485 mode In RS485 operations where there are multiple terminals
3. only the RS485 ports at each end of the network should have terminating impedance as described above To terminate the COM A port place a jumper at the location labeled Ch A RS485 To terminate the COM B port place jumpers at the location labeled Ch B RS485 Also for RS485 operation there must be a bias on the TRX and TRX lines If the adapter is not to provide that bias consult the factory for technical support Data Cable Wiring Signal Pin Connection Ain out 2 Ain out 3 1000 to Ground 5 Special 4 Wire RS485 Modes RS 485 2 Wire RS 485 2 Wire Terminated RS 422 b R 2 0 20 e Q O SEEE EEEE Sgggg EIE FERES 235 sisi HE D oa n e i M 25 OY T 8 3 O E 0 20 0 20 e e Figure 3 1 Option Selection Map This board has 2 separate channels which can be individually configured Each channel can be used in one of four modes 1 2 3 4 RS232 Install the top jumper in the RS232 position left RS422 Install the top jumper in the RS422 RS485 position right RS485 4 wire Install the top jumper in the RS422 RS485 position right and the RS485 Mode jumper RS485 2 wire Install the top jumper in the RS422 RS485 position right the RS485 Mode jumper the RS485 TxRx jumper and the RS485 TxRx jumper To provide a termination load in the RS485 mode install the appropriate RS485 TERM jumper The jumpers on the card must be p
4. MODEL USB COM 2SM USER MANUAL FILE MUSB COM 2SM A1a Notice The information in this document is provided for reference only Portwell does not assume any liability arising out of the application or use of the information or products described herein This document may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of Portwell nor the rights of others IBM PC PC XT and PC AT are registered trademarks of the International Business Machines Corporation Printed in USA Copyright 2007 by Portwell I O Products Inc All rights reserved WARNING ALWAYS CONNECT AND DISCONNECT YOUR FIELD CABLING WITH THE COMPUTER POWER OFF ALWAYS TURN COMPUTER POWER OFF BEFORE INSTALLING A CARD CONNECTING AND DISCONNECTING CABLES OR INSTALLING CARDS INTO A SYSTEM WITH THE COMPUTER OR FIELD POWER ON MAY CAUSE DAMAGE TO THE I O CARD AND WILL VOID ALL WARRANTIES IMPLIED OR EXPRESSED Warranty Prior to shipment Portwell equipment is thoroughly inspected and tested to applicable specifications However should equipment failure occur Portwell assures its customers that prompt service and support will be available All equipment originally manufactured by Portwell which is found to be defective will be repaired or replaced subject to the following considerations Terms and Conditions If a unit is suspected of failure contact Portwell Customer Service departme
5. along with 5 VDC power The board is powered from the USB port or alternate USB connector A second USB Input Connector P4 in parallel to the Type B connector is supplied This second connector is a USB OTG connector Auxiliary USB Connector This board has an optional feature You can cable an extra USB type A connector to the onboard USB1 1 hub This would provide an additional daisy chained USB 1 1 bus to which you can attach any 3rd party USB devices you may wish LED There are three LEDs present on the product functioning as follows a USB Power Present var Serial Port 1 Activity eg Serial Port 2 Activity USB 1 1 OR 2 0 BUS POWER ZBORT SPARE USB LED 1 1 HUB DOWNSTREAM E b d COMA UNE ACTIVITY USB BASED LED UART a en en RS485 RS422 s MODE RS232 422 or 485 Regen EE RED MODE i DRIVER vs DE RS 232 MODE SELECT 9 RS485 e 2 WIRE RS485 TERMINATION H or RS422 LOOPBACK SELECT MALE DB 9 CONNECTOR Figure 1 1 Block Diagram Chapter 2 Installation Software CD Installation These paragraphs are intended to detail the software installation steps as well as describe what is being installed The software provided with this board is contained on one CD and must be installed onto your hard disk prior to use To do this perform the following steps as appropriate
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7. harges caused by modifications or additions to Portwell equipment not approved in writing by Portwell or if in Portwell opinion the equipment has been subjected to abnormal use Abnormal use for purposes of this warranty is defined as any use to which the equipment is exposed other than that use specified or intended as evidenced by purchase or sales representation Other than the above no other warranty expressed or implied shall apply to any and all such equipment furnished or sold by Portwell TABLE OF CONTENTS Chapter 1 Introduction oooccco eh 5 Specifications d ami epi daa ddp Bake ege tede ue ad ed vid Dire 6 Figure 1 1 Block Diagram soa reinsa eE EE E A Re 8 Chapter 2 Installation uaaa 9 Hardware Installation deed wie bated e ERR PP ves b pp rure esu 9 Chapter 3 Option Selection 0 0 0c ns 10 Figure 3 1 Option Selection Map 000 cee eee 11 Chapter 4 Address Selection 0 000 ccc ttt 12 Chapter 5 Programming ee sri vuelo Hew opis Da Per nd Hee yaa OPE Oe hb Dads 13 Chapter 6 Connector Pin Assignments 0 0 00 eee tenes 14 Table 6 1 Serial Connector Pin Assignments 00 02 cece eee eee 14 Appendix A Application Considerations o oococccccooo ee 15 IMMOGUCTION PEE P 15 Table A 1 Connections Between Two RS422 Devices usus 15 Balanced Differential Signals 20 0000 cece tte eee 15 16 Tab
8. istics of the drivers and receivers are the same as in the RS422 Standard One difference is that the common mode voltage limit is extended and is 12V to 7V Since any driver can be disconnected or tristated from the line it must withstand this common mode voltage range while in the tristate condition The following illustration shows a typical multidrop or party line network Note that the transmission line is terminated on both ends of the line but not at drop points in the middle of the line TERMINATION RESISTORS AT BOTH ENDS ONLY KG TX ENABLE TX ENABLE RX ENABLE RX ENABLE TX ENABLE Fig TX ENABLE ure RX ENABLE RX ENABLE p A Ty pical RS485 Two Wire Multidrop Network RS485 Four Wire Multidrop Network An RS485 network can also be connected in a four wire mode In a four wire network it s necessary that one node be a master node and all others be slaves The network is connected so that the master communicates to all slaves and all slaves communicate only with the master This has advantages in equipment that uses mixed protocol communications Since the slave nodes never listen to another slave s response to the master a slave node cannot reply incorrectly Customer Comments If you experience any problems with this manual or just want to give us some feedback please email us at tech portwell com Please detail any errors you find and include your mailing a
9. ive Balanced Differential Signals The reason that RS422 and RS485 devices can drive longer lines with more noise immunity than RS232 devices is that a balanced differential drive method is used In a balanced differential system the voltage produced by the driver appears across a pair of wires A balanced line driver will produce a differential voltage from 2 to 6 volts across its output terminals A balanced line driver can also have an input enable signal that connects the driver to its output terminals If the enable signal is OFF the driver is disconnected from the transmission line This disconnected or disabled condition is usually referred to as the tristate condition and represents a high impedance RS485 drivers must have this control capability RS422 drivers may have this control but it is not always required A balanced differential line receiver senses the voltage state of the transmission line across the two signal input lines If the differential input voltage is greater than 200 mV the receiver will provide a specific logic state on its output If the differential voltage input is less than 200 mV the receiver will provide the opposite logic state on its output A maximum operating voltage range is from 6V to 6V allows for voltage attenuation that can occur on long transmission cables A maximum common mode voltage rating of 7V provides good noise immunity from voltages induced on the twisted pair lines The signal grou
10. le A 2 RS422 Specification Summary 00000 cee eee eee 16 RS485 Data Transmissior suse cie Ra x Rho ey RI ed bee RU Rm s 17 Figure A 1 Typical RS485 Two Wire Network 002 00e eee eee 17 Chapter 1 Introduction The USB COM 2SM is a USB interface device incorporating a USB 4 port hub internally to provide two ports of Serial Communication in one product The following paragraphs will first describe the Onboard Serial ports Serial Communication This Serial Adapter was designed for effective multipoint transmission in any one of three modes on each channel These modes are RS232 RS422 and RS485 ElA485 protocol The card features two independent asynchronous serial ports RS422 Balanced Mode Operation The board supports RS422 communications and uses differential balanced drivers for long range and noise immunity The board also has the capability to add load resistors to terminate the communications lines RS422 communications requires that a transmitter supply a bias voltage to ensure a known zero state Also receiver inputs at each end of the network should be terminated to eliminate ringing The board supports biasing by default and supports termination by jumpers on the card If your application requires the transmitter to be un biased please contact the factory RS485 Balanced Mode Operation The board supports RS485 communications and uses differential balanced drivers for long range and noise immunit
11. nd line connection is necessary in order to keep the common mode voltage within that range The circuit may operate without the ground connection but may not be reliable Parameter Conditions Tom E Ta Driver Output Voltage loaded LD and LDGND Driver Output Resistance 500 Driver Output Short Circuit Current 150 mA Driver Output Rise Time 10 unit interval Receiver Sensitivity 200 mV Receiver Common Mode Voltage Range 7V Receiver Input Resistance 4K0 Table A 2 RS422 Specification Summary To prevent signal reflections in the cable and to improve noise rejection in both the RS422 and RS485 mode the receiver end of the cable should be terminated with a resistance equal to the characteristic impedance of the cable An exception to this is the case where the line is driven by an RS422 driver that is never tristated or disconnected from the line In this case the driver provides a low internal impedance that terminates the line at that end Note You do not have to add a terminator resistor to your cables when you use the USB COM 2SM adapter Termination resistors for the RX and RX lines are provided on the card and are placed in the circuit when you install the Ch X LD jumpers RS485 Data Transmission The RS485 Standard allows a balanced transmission line to be shared in a party line mode As many as 32 driver receiver pairs can share a two wire party line network Many character
12. nt Be prepared to give the unit model number serial number and a description of the failure symptom s We may suggest some simple tests to confirm the failure We will assign a Return Material Authorization RMA number which must appear on the outer label of the return package All units components should be properly packed for handling and returned with freight prepaid to the Portwell designated Service Center and will be returned to the customer s user s site freight prepaid and invoiced Coverage First Three Years Returned unit part will be repaired and or replaced at Portwell option with no charge for labor or parts not excluded by warranty Warranty commences with equipment shipment Following Years Throughout your equipments lifetime Portwell stands ready to provide on site or in plant service at reasonable rates similar to those of other manufacturers in the industry Equipment Not Manufactured by Portwell Equipment provided but not manufactured by Portwell is warranted and will be repaired according to the terms and conditions of the respective equipment manufacturer s warranty General Under this Warranty liability of Portwell is limited to replacing repairing or issuing credit at Portwell discretion for any products which are proved to be defective during the warranty period In no case isPortwell liable for consequential or special damage arriving from use or misuse of our product The customer is responsible for all c
13. rimposed on common mode noise of 12 V or 7 V In case of communication conflict the driver receivers feature thermal shutdown The driver receiver used in RS232 mode is the ICL3243 Communication Mode The board supports Half Duplex communications with a 2 wire cable connection Half Duplex allows traffic to travel in both directions but only one way at a time RS485 communications commonly use the Half Duplex mode since they share only a single pair of wires Baud Rate Ranges The board has capability for baud rates up to 921 6K bps Serial Specifications Communications Interface 1 0 Connection Serial Ports Character length Parity Stop Interval Serial Data Rates Receiver Input Sensitivity Common Mode Rejection Transmitter Output Drive Capability Bus Type Environmental Operating Temperature Range Storage temperature Range Humidity Power Required Current Size Standard USB connector 2 male D sub 9 pin connectors 5 6 7 or 8 bits Even odd or none 1 1 5 or 2 bits Up to 921 6K 200 mV differential input 12V to 7V 60 mA with thermal shutdown USB 1 1 USB 2 0 Host Compatible 0 C to 60 C 50 C to 120 C 5 to 95 non condensing 120mA maximum see below 0 60mA per COM channel 4 inches wide by 4 inches deep by 1 25 inches high USB Connector The USB connector is a Type B connector and mates with the cable provided The USB port provides communication signals
14. roperly placed in order to have the card function properly Note Any unneeded jumpers that are installed can cause the adapter to function incorrectly 11 Chapter 4 Address Selection Use the provided driver to access the USB board This driver will allow you to determine how many supported USB devices are currently installed and each device s type This information is returned as a Vendor ID VID Product ID PID and Device Index The board s VID is 0x1605 and its PID is Ox8030 The Device Index is determined by how many of the device you have in your system and provides a unique identifier allowing you to access a specific board at will Chapter 5 Programming Sample Programs There are sample programs provided with the USB COM 2SM card in C Pascal QuickBASIC and several Windows languages DOS samples are located in the DOS directory and Windows samples are located in the WIN32 directory Windows Programming The USB COM 2SM card installs into Windows as COM ports Thus the Windows standard API functions can be used In particular gt CreateFile and CloseHandle for opening and closing a port gt SetupComm SetCommTimeouts GetCommState and SetCommState to set and change a port s settings gt ReadFile and WriteFile for accessing a port See the documentation for your chosen language for details Under DOS the process is identical to programming any 16550 or 16750 compatible UART
15. y RS485 operation involves switchable transceivers and the ability to support multiple devices on a single party line The RS485 specification defines a maximum of 32 devices on a single line The number of devices served on a single line can be expanded by use of repeaters This board also has the capability to add load resistors to terminate the communications lines RS485 communications requires that one transmitter supply a bias voltage to ensure a known zero state when all transmitters are off Also receiver inputs at each end of the network should be terminated to eliminate ringing The card supports biasing by default and supports termination by jumpers on the card If your application requires the transmitter to be un biased please contact the factory COM Port Compatibility The FT232BM UARTs are used as Asynchronous Communication Elements ACE These include 128 byte transmit amp 384 byte receive buffers to protect against lost data in multitasking operating systems while maintaining 100 percent compatibility with the original IBM serial port The system assigns the address es A crystal oscillator is located on the board This oscillator permits precise selection of baud rate up to 921 6K bps The driver receiver used SP491 in non RS232 modes is capable of driving extremely long communication lines at high baud rates It can drive up to 60 mA on balanced lines and receive inputs as low as 200 mV differential signal supe
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