RS232 to Rs485 Circuit, PCB

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tico70

Joined: 24 Mar 2002
Posts: 11

20 Mar 2004 19:23 rs485 circuit

Hello,

I was looking for this circuit several days ago. Finally Elektor published an article about it

Here is a copy of the article. Including SCHEMATICS, PCB, etc.

I hope this will be helpfull for someone. Very Happy

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boleft

Joined: 10 Sep 2002
Posts: 10

17 Jun 2004 14:37 rs232 rs485 converter schematic

do you know send data control & RTS control?

boleft

Joined: 10 Sep 2002
Posts: 10

17 Jun 2004 14:48 rs232 to rs485 circuit

I will design usb to rs485, do you know any SCHEMATICS? ths!

ASIC

Joined: 18 May 2001
Posts: 220

20 Jun 2004 22:32 rs232 rs485 circuit

I think the fastest is to use a Cypress USB chip and a RS232 to RS485 converter. Problem with the windows drivers though. Does WinXP have a USB serial port driver as standard?

ASIC

Just a note... if you DESIGN something, you draw the schematic by yourself. If you copy, or build, or assembly something, you probably get the schematic from somewhere Smile

ME

Joined: 14 Mar 2002
Posts: 1523
Helped: 13

01 Jul 2004 23:03 rs485 schematic

boleft wrote:

I will design usb to rs485, do you know any SCHEMATICS? ths!

I think the easiest is to use an USB to serial converter chip and RS485 drivers.

Here is an FTDI application note with complete schematic in OrCAD and PDF:
ULTRABAUD USB <=> RS422/RS485 SERIAL CONVERTER ( 300 to 2000k baud )
www.ftdichip.com/Files/usb-422.zip

Please note that the USB chip used in this schematic (FT8U232AM) have been replaced with a 2nd generation chip (FT232BM) which requires fewer external components.

A 3rd generation chip (FT2232C) have also been introduced recently. This chip has two seperate serial / GPIO ports, but if you only need one RS485 port you can just use FT232BM, this is still in production and is cheaper than the dual port FT2232C.
www.ftdichip.com

I couldn't find an upgraded schematic for FT232BM RS485 interface, but you can find FT232BM RS232 interface schematics.
If you look a both schematics you could figure out what to change/remove to upgrade the RS485 schematic to use FT232BM (or FT2232C).

ME

Joined: 14 Mar 2002
Posts: 1523
Helped: 13

01 Jul 2004 23:29 rs232 to rs485 schematic

Now I found USB <-> RS485 schematics for 2nd generation FT232B and USB <-> dual RS485 schematics for 3rd generation FT2232C in their respective datasheets:

FT232B (look at figure 11 page 19) www.ftdichip.com/Documents/ds232b14.pdf
FT2232C (look at figure 16 page 31) www.ftdichip.com/Documents/ds2232c12.pdf

You can also find USB <-> RS232 and USB <-> RS422 interface examples in these datasheets.

ahmet2004

Joined: 01 Jan 2004
Posts: 62
Helped: 1

15 Sep 2004 2:10 rs232 to rs485 converter schematic

( 300 to 2000k baud ) ?

ME

Joined: 14 Mar 2002
Posts: 1523
Helped: 13

15 Sep 2004 10:52 rs232 rs485 schematic

ahmet2004 wrote:

( 300 to 2000k baud ) ?

Yes 300 to 2000k baud, I already wrote that.
Why do you ask again?

kapong

Joined: 21 Jul 2002
Posts: 8

28 Apr 2005 10:55 rs 485 circuit

will design usb to rs-422, do you know any SCHEMATICS? ths!

Added after 1 minutes:

will design usb to rs-422, do you know any SCHEMATICS? ths!

yangxh

Joined: 26 Nov 2004
Posts: 99

30 May 2005 2:33 rs485 to rs232 circuit

I ask if 485 is faster than 232?

IanP

Joined: 05 Oct 2004
Posts: 6476
Helped: 1540
Location: West Coast

30 May 2005 2:44 rs485 to rs232 converter circuit

yangxh,

Here is comparison of RS-232 and 485:
http://www.hw.cz/english/docs/rs485/rs485.html

Regards,
IanP

TheHungry

Joined: 06 Mar 2002
Posts: 214
Helped: 2

31 May 2005 11:38 usb to rs485 schematic

http://www.bb-elec.com/current_products.asp

many schematics

binu G

Joined: 09 Jan 2003
Posts: 738
Helped: 9
Location: Bangalore

22 Oct 2005 8:16 usb to rs485 converter schematic

reference to the design doc attached by tico70

what i have noticed that only 2 pin of the RS232 D9 connector is connected with the max232 chip.

for a PC with master and 10 controllers as salve having RS485 interface is this sufficient, or i need to use some of other pins in the D9 Connector, i mean the signals like CTS RTS etc.

why this is not used in the design

artem

Joined: 22 May 2003
Posts: 1650
Helped: 91
Location: Turan

24 Oct 2005 1:23 rs232 to rs485 pcb

2 binu G
Do you mean CTS and RTS ?
If so , these signals are not used as there is no flow control between master and slaves on RS485 interface - it must be (if necessary) implemented by overlaying protocols above physical layer (RS485).

khongai

Joined: 20 May 2005
Posts: 245
Helped: 5

26 Oct 2005 6:35 usb to rs485 circuit

another link:

http://www.lammertbies.nl/comm/info/RS-485.html

yangxh

Joined: 26 Nov 2004
Posts: 99

14 Nov 2005 10:09 rs485 converter schematic

I ever did a USB-485 convertor.Now I am debugging the circuit.What's the advantage are the convenience,the reliability and the high speed.

nusliqiang

Joined: 05 May 2006
Posts: 21
Helped: 1

30 Jun 2006 9:27 ft232bm rs485

using max3081 also can do.

thyago__ogawa

Joined: 14 Jan 2007
Posts: 1

09 Feb 2007 18:51 rs485 schematics

Can i use the 74HC123 component instead of the 74HCT123 piece in the schematic?

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09 Feb 2007 18:51 Ads

yangxh

Joined: 26 Nov 2004
Posts: 99

03 Mar 2007 11:06 rs232 to rs485 circuits

boleft wrote:

I will design usb to rs485, do you know any SCHEMATICS? ths!

I know FTDI com have some chips may help this.

Added after 1 minutes:

max3081 max3082 ma485 max487 and so on.

matt518000

Joined: 30 Mar 2007
Posts: 1

30 Mar 2007 3:02 rs485 to rs232 converter schematic

To find cheaper and better Rs232/485/422 Converter , see the http://store.era-ele.com

As one professional manufacturer of Rs232/485/422 Converter in China, all our efforts are directed to requite customers for their support with products of high quality and favorable prices.

our converters with both isolation and surge protection, enclosed terminal blocks for tamper resistance and DIP switches for configuration. Isolated power and ground generated internally. No power is drawn from the host RS-232 port. LEDs indicate data traffic. Only RS-232 side requires a power supply. it is a basic isolated converter. The RS-232 side draws power from the RS-232 handshake lines of the connected PC. At least one handshake line must be asserted (high) to power the converter. If high handshake lines aren't available, it is recommended. The RS-422/485 side is powered by an external power supply.

Features:
-Powered from double side, 2500V isolation, 1500W surge protection
-Transmit distanc reach up to 1800M at the rate of 115.2kbps
-Adopt interface atuo-adapt technology, no DIP switch setup,random switcht RS-485/RS-422 interface
-Automatic send data control, auto distinguish and sense direction about data transfer
-Auto sense serial signal rate, zero delay automatic transmit

If any of the items listed in the website meets you interest ,please let us have you specific enquiry and our quotation will be forwarded without delay .If have any question ,please free to contact me! I will reply you as soon as possible.

Email：store(at)era-ele.com

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Last edited by matt518000 on 25 Sep 2008 5:14; edited 1 time in total

electrosysdo

Joined: 09 Jul 2003
Posts: 6

05 Apr 2007 15:16 rs-485 circuit

do you know any schematics for rs232 to profibus

funnynypd

Joined: 09 May 2007
Posts: 916
Helped: 21
Location: USA & Canada

11 Nov 2007 18:53 rs232 rs485 converter circuit

Here is one low cost (us $49.99) RS232 to RS485/SAE1708 converter(made in USA and life-time warranty):
http://www.auelectronics.selfip.com/System-485.htm

Here is the product pictures :
Front view:
RS232 to Rs485 Circuit, PCB

Rear view:
RS232 to Rs485 Circuit, PCB

PCB layout:
RS232 to Rs485 Circuit, PCB

lss_00

Joined: 14 Aug 2007
Posts: 2

24 Nov 2007 16:26 rs232 to 485 circuit

Here is a RS232 to Rs485 Circuit .
Hope it will help.

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abdallayad

Joined: 04 Jun 2008
Posts: 5
Helped: 2

04 Jun 2008 17:47 rs485 interface schematic

this is autoamtion PLC

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robinsonl

Joined: 14 Jun 2008
Posts: 4

27 Aug 2008 14:54 circuit rs232 to rs485

USB To RS-485

http://store.era-ele.com/hxsp2108f-usb-to-rs485-interface-converter-p-76.html

maheshtumkur

Joined: 17 Oct 2008
Posts: 1

17 Oct 2008 6:23 rs485 to rs232 schematics

Hello
I am looking for USB to RS232 level converter can you please help me regarding this.. I go through the FT232 but i din't get full details about that,and for that any extra drivers is required or not.

laktronics

Joined: 06 Jan 2007
Posts: 945
Helped: 156

29 Oct 2008 15:08 circuit rs232 to 485

Hi,
Yes, you need a MAX232 like level converter. The basic chip FTD232 gives only TTL level I/Os for RS232.

Regards,
Laktronics

reza_agha

Joined: 24 Apr 2009
Posts: 1

24 Apr 2009 7:39 232 to 485 circuit

there are two projects on net which may be usefull for you,
1st google for "Igor USB", which someone from slovaki made a usb to serial converter using ATMEL AVR microcontroller.
2nd in sourceforge.net look for com0com project which emulates a com port in system.

idea: you can implement your own usb to rs232 converter using igor's circuit, but it did not add a new com device to system. use com0com to define one, and redirect transactions to your own hardware (Igore).

good luck;