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Replace RS485 with PLC design information

Ervis
Prodigy 100 points
Other Parts Discussed in Thread: AM3359

Dear Sir

Hello.

I am developing a new design where  dc power line will be use for data comunication too. I check on the texas webpage and forum on PLC thus  is the 

TMDSPLCKITV4-CEN develpment board a good start. The actuall system which needs a PLC design is as follow:

 The acquisition Box is a complete  system which got RS485 interface, a Windows  embedded CE, LCD display.

The devices 1 and 2 are load cells which comunicate with the Acquisition Box in half duplex RS485 baud rate 115200

cable length between devices and acq box 50meter.

Any advice what I can choose as a development kit?

thankyou

Ervis 

  • 0
    TI__Genius 9930 points

    Hi Ervis,

    From the description , are you trying to develop a system where you are using the Power line comm as an option to the RS485 ? or are you trying to build a PLC system that would interface to this RS485  existing system ?

    24VDCPLCEVM reference design would be useful if its a total replacement .

    Regards .

  • 0 in reply to MEGHANA MANAVAZHI
    Prodigy 100 points

    Hi Meghana

    I am trying to build a PLC system that would interface to  existing RS485 system. Thus I am still searching, the data concentrator TMDSDC3359 has The" RS-485 ports are designed and tested to work up to 9600 bits/sec" so it is not the right one to buy for my design. I was searching one other evaluation board TMDSPLCKITV4-CEN and it has "Baud Rate = 57600" and this got a baud rate which is good but not the best as the actual system with 4 wires got a baud rate of 115200 .

    Thus my design is to use 2 wires for power and data transmission. Moreover the design must interface with 2 RS485 devices as I show on schematic and the baud rate wich is used between acquisition box(host computer with windows ce embedded) is 115200.

    kind regards

    Ervis

     

  • 0 in reply to Ervis
    TI__Genius 9930 points

    hi Ervis,

    So the intention is to get a board that would act as a gateway from RS-485 to PLC and this PLC would communicated with the acquisition board on Power line ?

    The  TMDSPLCKITV4-CEN does not have an RS-485 interface that can act as a interface between PLC and RS-485 .

    the Data concentrator board does have RS-485 ports ? why do you say you cannot use this board ?

    Regards .

  • 0 in reply to MEGHANA MANAVAZHI
    Prodigy 100 points

    Dear MEGHANA

    Hello.

    First, I am sorry that I did not reply to you earlier. Let me get back to the point.

    Yes the intention is to get a board that would act as a gateway from RS-485 to PLC and the PLC would comunicate with the acquisition board on Power line.

    ----------------------------------------------------------------------------------------------- 

    You are right the TMDSPLCKITV4-CEN does not have an RS485 and RS232 neither but I will put on my board(new design board)  the RS485 driver.

    I was concern about the speed of communication which the   TMDSPLCKITV4-CEN has:(from datasheet)

    To communicate with the SCI, the following requirements must be met.

    Baud Rate = 57600 (this is a baud rate acceptable for my aplication)

    Message Data Bits = 8

    Stop Bits = One

    Parity = None

    Handshake = None

    RTS Enable = True

    ----------------------------------------------------------------------------------------------

    Refer to Data concentrator I do know that it has 3xRS485 but in this case the permitted speed is low.

    my concern was again to speed comunication as it says that:(from data concentrator data sheet)

    RS-485 Ports
    Three half-duplex RS-485 ports are supported by the Smart DC EVM through the J22, J23 and J24 connectors....
    NOTE
    The RS-485 ports are designed and tested to work up to 9600 bits/sec.

    Operation above this rate is not supported.
    Each RS-485 port uses a half-duplex transceiver to interface to the RS-485 bus. Furthermore, the UART pins on the
    AM3359 processor are isolated from the transceiver using opto-couplers....

    I would like to consider the data concentrator but from data sheet information it does not give the possibility to comunicate with higher baud rate.

    This is my issue and why  did not decide yet which evaluation board to buy for my development design.

    regards

    Ervis 

     Dear Sir

    Hello

    Can anyone help me/answer me about the above questions please?

    regards

    Ervis