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coexisting LFHDX systems

Colin Watson
Intellectual 770 points

Other Parts Discussed in Thread: TMS3705

Hi,

I have designed a TMS3705  based Selective Animal Feed Gate as an upgrade to a widely used product within beef and dairy cow research establishments.

With TI 134.2kHz HDX the dominant standard for Cattle I.D.  I need to choose a strategy to enable the selective feeding access gate to coexist with mainline ID systems to ISO11874/5 standards.

Under test, the simplest option attempted  has been to load a copy of the eartag ID into the neck halter pendant of the selective feed gate system so that which ever tag dominates as an animal passes through a passage ID field, the correct data is recorded. We use the RI-TRP-W9QL-30 tag  and our TMS3705 system reads the first 3 bytes of the ID to detect parity with an EEROM ID loaded via a learning routine.

The TMS3705 implementation has been easy to design and at a prototype level is surviving the hostile feed fence environment very well. I chose the device because of the reliability of the LFHDX system as a proximity RFID operating over a 4-6 inch range. I drive the antenna coild from a 9v pulse using a buffer.  Feels a good system if I can manage this coexistence with formal ID systems

The quetstion is What coexistence strategies are there to deal with an animal carrying two HDX tags ?

No problems at all with the TI technology.

Many thanks,

Colin

 

  • 0
    TI__Intellectual 1535 points

    Hi Colin,

    you need to consider two things:

    1.) Coexistence of two or more readers in proximity

    You need to take care of interferences of two LF RFID readers in close proximity, in case these readers interfere with each other, these need to be synchronized (only one reader is active at the time). There has been a standard defined how to do that: ISO 24631-7, this standard is available on the ISO site: http://www.iso.org/iso/home.html. Close proximity means a couple of feet separation for low power hand held devices and up to a couple of hundred feet for high power gate readers.

    2.) Coexistence of two or more ISO11784/5 tags

    In case the tags are separated from each other (e.g. 10 inches) they can be read as long as these tags are moving; in a gate application, it is no problem to detect 2 tags sequentially as long as the tags are moving through the gate: The readers a capable locking to the stronger of the 2 FSK modulated tag responses.

    Best regards,

    Klemens

     

  • 0 in reply to KSA
    Intellectual 770 points

    Very Many thanks Klemen,

     

    re-close proximity readers. We have randomised the scanning cycles  in a 300mS repetition and in this way animals are only likely to be blocked by the 50mS power period for vry short intervals which are not noticed by the animal. Since we are not capturing IDs or data this is acceptable to our application.

    Yes under test syncing the data in the two keys works, We would provide users with the means to copy eartag contents to our selective access key/tag.

    I just wonder if you know of any legal inhibition to copying identity tags in this way ?    Otherwise it appears the most practical solution.

    I greatly appreciated your prompt response.

     

    Many thanks,

     

    Colin

  • 0 in reply to Colin Watson
    TI__Intellectual 1535 points

    Colin,

    there are no legal limitations copying the ID of an eartag to a R/W tag: The R/W tag can be clearly differentiated from an animal ID tag (ISO11784/5 compliant) through the differently hard coded start bytes.

    Best regards,

    klemens

  • 0 in reply to KSA
    Intellectual 770 points

    Thanks again Klemens,

    Excellent. I think that clears the way round our coexistent realities.

     

    Colin