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RS232 to Rs485 Circuit, PCB

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tico70

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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. :D
 

boleft

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rs232 rs485 converter schematic

do you know send data control & RTS control?
 
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boleft

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rs232 to rs485 circuit

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

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ASIC

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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 :)
 

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ME

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rs485 schematic

boleft said:
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).
 

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ME

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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

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rs232 to rs485 converter schematic

( 300 to 2000k baud ) ?
 

ME

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rs232 rs485 schematic

ahmet2004 said:
( 300 to 2000k baud ) ?
Yes 300 to 2000k baud, I already wrote that.
Why do you ask again?
 

kapong

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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

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rs485 to rs232 circuit

I ask if 485 is faster than 232?
 

IanP

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rs485 to rs232 converter circuit

yangxh,

Here is comparison of RS-232 and 485:
**broken link removed**

Regards,
IanP
 

TheHungry

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usb to rs485 schematic

**broken link removed**

many schematics
 

binu G

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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

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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).
 

yangxh

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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

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ft232bm rs485

using max3081 also can do.
 

thyago__ogawa

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rs485 schematics

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

yangxh

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rs232 to rs485 circuits

boleft said:
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

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rs485 to rs232 converter schematic

To find cheaper and better Rs232/485/422 Converter , see the **broken link removed**

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@era-ele.com
 

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