Acces I/O products USB-COM232-4A User Manual Download Page 22 | Manualshive

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Acces I/O products USB-COM232-4A User Manual Download Page 22

Manual USB-FLEXCOM4

22

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 transmits to all slaves and all slaves transmit to 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.

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Summary of Contents for USB-COM232-4A

Page 1: ...eet San Diego CA 92121 858 550 9559 Fax 858 550 7322 contactus accesio com www accesio com MODEL USB FLEXCOM4 USB to Four RS 232 422 485 Serial Ports and MODEL USB COM232 4A USB to Four RS 232 Serial...

Page 2: ...Manual USB FLEXCOM4 2 FILE MUSB FLEXCOM4 C3...

Page 3: ...CCES 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 by ACCES I O Products Inc 10623 Roselle Stree...

Page 4: ...parts not excluded by warranty Warranty commences with equipment shipment Following Years Throughout your equipment s lifetime ACCES stands ready to provide on site or in plant service at reasonable...

Page 5: ...Jumper Labels 11 Terminations 11 Figure 3 2 Simplified Termination Schematic 11 Figure 3 3 Option Selection Map 12 Default Shipping Configuration 13 Connectors and Indicator Functions 13 Chapter 4 US...

Page 6: ...se 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...

Page 7: ...re 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...

Page 8: ...Manual USB FLEXCOM4 8 Figure 1 1 Block Diagram Only one full serial channel shown Baud Rates Baud rates up to 921 6kbps are supported in RS 422 and RS 485 modes while RS 232 has a limit of 230 4kbps...

Page 9: ...a type A to locking B cable PLK Substitutes standard DC power input jack with a latching Molex connector Special Order Custom baud rates are achievable by using a different integrated circuit chip Co...

Page 10: ...Installing the Adapter Before installing the adapter carefully read the OPTION SELECTION section of this manual and configure the adapter according to your requirements In Windows the SETUP EXE progra...

Page 11: ...485 operation Figure 3 2 Simplified Termination Schematic In RS485 operations where there are typically multiple terminals only the RS485 devices at each end of the network the serial COM port at one...

Page 12: ...d that this unit will function as the Master in 4 wire RS485 mode In this case configure the jumpers for RS422 It is also possible to use it as a Slave In this case install the 2 position jumper in th...

Page 13: ...of the supported modes you ll need to remove the lid and configure the jumpers for that port Connectors and Indicator Functions USB Connector Type B high retention design Embedded USB Connector Mini...

Page 14: ...ation 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 Address Map The core of the...

Page 15: ...minal Program Screen Shot Windows Programming The board installs into Windows as COM ports Thus the Windows standard API functions can be used In particular CreateFile and CloseHandle for opening and...

Page 16: ...connection DB 9 Male Pin for each of Ch A D RS 232 Signals Industry Standard RS 485 Signals 2 Wire RS 422 Signals Also 4wire RS485 Ch x 1 DCD RX Ch x 2 RX TX RX TX Ch x 3 TX TX RX TX Ch x 4 DTR Ch x 5...

Page 17: ...ype USB 2 0 High Speed USB Connector Type B high retention Embedded USB 5 pin header Molex part number 53047 Mating connector housing is Molex part number 51021 0500 Environmental Operating Temperatur...

Page 18: ...Connections between two RS422 devices with CTS ignored should be as follows Device 1 Device 2 Signal Pin No Signal Pin No Gnd 5 Gnd 5 TX 2 RX 9 TX 3 RX 1 RX 9 TX 2 RX 1 TX 3 Table A 1 Connections Betw...

Page 19: ...ut 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 transmi...

Page 20: ...ty line mode As many as 32 driver receiver pairs can share a two wire party line network Many characteristics of the drivers and receivers are the same as in the RS422 Standard One difference is that...

Page 21: ...Manual USB FLEXCOM4 21 Figure A 1 Typical RS485 Two Wire Multidrop Network...

Page 22: ...y that one node be a master node and all others be slaves The network is connected so that the master transmits to all slaves and all slaves transmit to the master This has advantages in equipment tha...

Page 23: ...anual or just want to give us some feedback please email us at manuals accesio com Please detail any errors you find and include your mailing address so that we can send you any manual updates 10623 R...

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