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Electronics required for transmission of signals in fibre

  1. Jun 8, 2010 #1
    HI ALL
    Well i want to know the power electronics required to transmit signals for sensors,limit switches ,push buttons up to PLC, and if analog device signals like potentiometer could be transmit tted with these ,how can i do this .
    i am using Plastic Optical Fibre and please help me with the basic things to the complicated ones Bragg grating or isolators are required for these?? can i use couplers to insert one POF signal into another , what will be the bandwith criteria.is there any issues with discrete signals like sensors and push buttons with bandwith selection for cables.?
    and do i have to address signals from transmitting end to recieving end or the Tx and Rx will do the neccesary things if i am using DWDM.
     
  2. jcsd
  3. Jun 8, 2010 #2
    help please .......................if anyone is not able to understand the job i want to do please ask me again. i will clear your questiions that what i want to do with POF.
     
  4. Jun 8, 2010 #3

    Integral

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    Gold Member

    Your question is just too broad there is no way we can give you the information you need in this format. I suggest that you break the problem up, perhaps read up on the PLC you are using. We help best with specific questions. Good luck.
     
  5. Jun 9, 2010 #4
    Help neede to transmit sensor signals in optical fibre

    how can i transmit the sensor signals ( inductive,proximity etc.) thru optical fibre ,
    i want to know the power electronics use in this.
     
  6. Jun 9, 2010 #5

    berkeman

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    Staff: Mentor

    Re: Help neede to transmit sensor signals in optical fibre

    Here's an introduction:

    http://en.wikipedia.org/wiki/Fiberoptics

    Let us know if you have specific questions in that reference.
     
  7. Jun 9, 2010 #6
    Re: Help neede to transmit sensor signals in optical fibre


    well this is all about optical fibre,i want to try out transmitting sensors and limit switches signals thru Plastic optical fibre,cable is rather cheap than copper as the no. of devices are large ,but the electronics behind it is a liitle confusing with new technologies emerging.
    i want to know the electronic circuitry needed to do this,
    i am attaching a word file with image drawn by me on CAD please check if i will require more than this.
    is it complete ? please help .!!!
     

    Attached Files:

  8. Jun 10, 2010 #7

    berkeman

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    Re: Help neede to transmit sensor signals in optical fibre

    Something like that can work, but I don't think you'd use different wavelengths of light in the fiber to multiplex the signals. What bandwidth (BW) do you need for each signal? You should be able to just digitize the signals and send the combined/encoded digital data through your single fiber, assuming your data BW requirement per signal is not too high.
     
  9. Jun 10, 2010 #8
    Re: Help neede to transmit sensor signals in optical fibre

    yes actually i am also not getting any specification for the sensors in bits per second for normal proximity or capacitive sensors or limit switches,but i assume that it will be around 16~50 bits /sec. and all goes to plc .thats why for replacing the junction boxes and the copper cables i am using POF which is cheap.
    but shouldnt i have to multiplex the incoming signals? coz number of devices in each part u can say will be around 30~50 and total will be 120 devices over all. so can you please get me to some details how can i think for my power electronics.
    what all will i have to use. coz this is a reasearch but may be if it will become succesful we will plan for mass production
    thanku
     
  10. Jun 11, 2010 #9

    berkeman

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    Re: Help neede to transmit sensor signals in optical fibre

    Your sensors sound like they are all low bandwidth, so you need to think about how you can combine all of their digital data into a frame of data, and design the frame structure and the number of frames per second that you want to send. It's a common networking design task. Take a look at CAN or other industrial automation network designs for more ideas.
     
  11. Jun 11, 2010 #10
    Re: Help neede to transmit sensor signals in optical fibre

    Hello Sugandh,
    Wavelength Division Multiplexing is a technique normally utilised by really high-bandwidth systems, where the individual wavelengths typically each carry up to tens of GB/s each. This type of multiplex would normally by carried on low-loss mono-mode glass fibres. The gratings etc. needed to assemble the multiplex would be compatible with this type of fibre.

    The type of application you are describing with modest telemetry bandwidths over plastic fibre should only require time-division multiplexing using a single wavelength.
     
  12. Jun 14, 2010 #11
    Re: Help neede to transmit sensor signals in optical fibre

    thanks very much ,but can TDM be sufficient for the No. of devices i want to connect(still all will not operate at same time.)
    But that`s the problem how can i calculate for my system and cables if i dont know the bandwith of my devices, is there any list where i can get the spec of sensors in bps.i am not getting googling it .can you help out with the power electronics, coz i am afraid of its cost,whther all trancivers and photodiodes,mux and demux would be sufficient for my data transmission or there will be a scary electronics with it.
    again i am attaching a doc. ,if you can tell me about that module that what all will be required for it.
    the field devices are sensors,push buttons, limit witches etc. and connecting to a connector from there taking to a module which should be compact in structure with all electronics to enter in POF and entering in main panel converting it and inputting those signals in PLC.
    thanks for you help in advance.
     

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