How to link RFID to PLC?

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How to link RFID to PLC?

Postby jenshen418 » Sat Dec 03, 2011 1:55 pm

I'm doing a FYP "parking system" that use RFID and PLC... anyone know how to link this 2 device?
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Re: How to link RFID to PLC?

Postby ABSF » Sat Dec 03, 2011 2:57 pm

jenshen418 WROTE:I'm doing a FYP "parking system" that use RFID and PLC... anyone know how to link this 2 device?


In what roles are your RFID and PLC playing in the parking system of yours?
Does your PLC have UART or USB interface and can it play USB Host?

Take a look at the DIY Projects offered by cytron. You can also buy the RFID - RS232 interface itself.

PR8B

PR25

RFID reader RS232

Allen
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Re: How to link RFID to PLC?

Postby shahrul » Sat Dec 03, 2011 11:07 pm

jenshen418 WROTE:I'm doing a FYP "parking system" that use RFID and PLC... anyone know how to link this 2 device?

Did your PLC have USB interface? Mostly PLC communication use RS232/RS485 with Modbus protocol.
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Re: How to link RFID to PLC?

Postby jenshen418 » Sun Dec 04, 2011 6:54 pm

Rfid is used to detect user and only valid user can enter to the parking. After the RFID confirm the user is valid user, PLC will control the barrier to open and allow user to enter. PLC i m going to use is OMRON CQM1H. It use rs232 port... can pc connect with 2 rs232 at the same time?
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Re: How to link RFID to PLC?

Postby jenshen418 » Sun Dec 04, 2011 6:59 pm

The plc i use also use RS232.. now i m thinking of hw to connect this 2 things... I m new here and this 2 type of device. So i m wana know more about them...
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Re: How to link RFID to PLC?

Postby ABSF » Sun Dec 04, 2011 7:37 pm

jenshen418 WROTE:Rfid is used to detect user and only valid user can enter to the parking. After the RFID confirm the user is valid user, PLC will control the barrier to open and allow user to enter. PLC i m going to use is OMRON CQM1H. It use rs232 port... can pc connect with 2 rs232 at the same time?


So your RFID will read the RFID tags and send the result to a PC thru UART. Then your PC would identify the users to see if they are authorised and send commands to PLC via UART to tell it to open the barrier. Is that how your system works?

If you're using a PC as the decision maker and database there should be no problem. You can buy USB-UART from cytron (UC00A or UC00B) and plug 2 of these to your PC and your PC will see them as COMx and COMy. Add MAX232 to the UART if you need RS232 signal levels.

Not sure if your PLC can do the job of the PC or else you can connect the RFID directly to your PLC.

Allen
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Re: How to link RFID to PLC?

Postby jenshen418 » Sun Dec 04, 2011 8:03 pm

ABSF WROTE:
jenshen418 WROTE:Rfid is used to detect user and only valid user can enter to the parking. After the RFID confirm the user is valid user, PLC will control the barrier to open and allow user to enter. PLC i m going to use is OMRON CQM1H. It use rs232 port... can pc connect with 2 rs232 at the same time?


So your RFID will read the RFID tags and send the result to a PC thru UART. Then your PC would identify the users to see if they are authorised and send commands to PLC via UART to tell it to open the barrier. Is that how your system works?

If you're using a PC as the decision maker and database there should be no problem. You can buy USB-UART from cytron (UC00A or UC00B) and plug 2 of these to your PC and your PC will see them as COMx and COMy. Add MAX232 to the UART if you need RS232 signal levels.

Not sure if your PLC can do the job of the PC or else you can connect the RFID directly to your PLC.

Allen


may i know how to connect PC to RFID/PLC (RS232) through UART?
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Re: How to link RFID to PLC?

Postby ABSF » Sun Dec 04, 2011 8:37 pm

jenshen418 WROTE:may i know how to connect PC to RFID/PLC (RS232) through UART?


Using UC00B from cytron.
UC00B.jpg
UC00B USB-UART interface
UC00B.jpg (66.28 KiB) Viewed 6348 times


To connect the PLC to PC, you'll need to add a UART to RS232 converter chip called MAX232 to UC00B above. Try googling MAX232 to see the connection and datasheet. If you're able to find USB-RS232 interface elsewhere, then MAX232 is not needed.

The RFID READER - RS232 from cytron already has the RS232 built in so it just goes into the COM port of your PC if there is one (correct me if I am wrong). OR else you'll need a second UC00B to connect the RFID to your PC.

Allen
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Re: How to link RFID to PLC?

Postby jenshen418 » Sun Dec 04, 2011 10:37 pm

ABSF WROTE:
jenshen418 WROTE:may i know how to connect PC to RFID/PLC (RS232) through UART?


Using UC00B from cytron.
UC00B.jpg


To connect the PLC to PC, you'll need to add a UART to RS232 converter chip called MAX232 to UC00B above. Try googling MAX232 to see the connection and datasheet. If you're able to find USB-RS232 interface elsewhere, then MAX232 is not needed.

The RFID READER - RS232 from cytron already has the RS232 built in so it just goes into the COM port of your PC if there is one (correct me if I am wrong). OR else you'll need a second UC00B to connect the RFID to your PC.

Allen


the PLC i use also using RS232 but my pc onli have 1 RS232 port. How can i connect 2 RS232 (1 is from PLC, 1 is from RFID) in the same time? Sry cz asking so much of question. I dun have much knwledge on this field.
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Re: How to link RFID to PLC?

Postby shahrul » Sun Dec 04, 2011 11:24 pm

jenshen418 WROTE:the PLC i use also using RS232 but my pc onli have 1 RS232 port. How can i connect 2 RS232 (1 is from PLC, 1 is from RFID) in the same time? Sry cz asking so much of question. I dun have much knwledge on this field.

RS232 on PLC doesn't communicate with normal RS232 signal. It have own communication protocol called Modbus. So, if you connect RFID directly to PLC, it's can't work.

So, I suggest RFID connect to PIC, then PIC talk to PLC using Modbus. You can see Modbus code on PIC here.
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