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"High speed input" modules for absolute encoders

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  • "High speed input" modules for absolute encoders

    It would be very helpful if Automation Direct would create a high speed input type module designed for absolute encoders with both Sin/Cos and SSI data interface capability. Absolute encoders are starting to get pretty nice and are gaining in popularity. They often have 16 and sometimes even 18-bit position information so the module would need to be made future proof enough to at the very least understand 18-bit, though preferably it would just use a 24-bit capable interface so it would work even as encoders get even better. The inputs also need to be able to understand single turn input resolution, as well as multi-turn data information (which would be an additional 24-bit input interface).

    Both Productivity and Do-More modules would be nice, but I would most like these type of modules in Productivity line as I already use that whenever I need high resolution stuff already.


    Here are examples of high resolution absolute encoders:
    https://www.sick.com/us/en/encoders/...-ssi/c/g248085
    http://encoder.com/products/absolute...s/model-a58hb/

    And a paper on some of what would be required to interface with SSI:
    http://encoder.com/core/files/encode...les/TB-529.pdf

    And another paper on a Texas Instruments product that has some good info on interfacing with Sin/Cos encoders which are somewhat similar to quadrature incremental:
    http://www.ti.com/lit/ug/tidua05a/tidua05a.pdf

    http://www.diegm.uniud.it/petrella/A...in_encoder.pdf





    Also, AD should update its encoder line and start selling some high resolution absolute encoders like these.
    Last edited by MikeN; 11-26-2019, 04:32 PM.


  • #2
    possibly a signal conditioner (not tied to a particular plc) that has multiple output types that can be made to interface with existing hardware.

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    • #3
      The AMCI ANE2E interface looks interesting.
      thePLCguy

      Bernie

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      • #4
        They should just switch to EtherCAT for all motion products. I hardly use anything else now. Even our stepper drives are EtherCAT.

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        • #5
          I see that SICK has some that speak Ethernet IP. I have no idea if that will work for your application but the productivity productivity series should be able to talk to it.

          https://www.sick.com/us/en/encoders/...etip/c/g244406

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          • #6
            Originally posted by z28z34man View Post
            I see that SICK has some that speak Ethernet IP. I have no idea if that will work for your application but the productivity productivity series should be able to talk to it.

            https://www.sick.com/us/en/encoders/...etip/c/g244406
            I looked at those about a year ago, unfortunately they are too slow. The fastest response time on a clear network with no collision is 5ms, and I would want something closer to 1-2ms on average.
            The SSI communicating encoders with a theoretical 24-bit resolution, running at 500kHz clock rate from a master controller would be able to theoretically send out its current position every 0.05ms. Current encoders are less than 24-bit, so they would have less data to send, and even if you slowed down the clock rate being sent to the encoder you could still keep it 1ms or less response time.

            Sin/Cos analog can also update similarly in speed since depending on the MHz speed the DSP chip used for the input is running at, as it is just processing the coarse incremental count and the processed fine count of the sine waves very similar to current HSI modules with quadrature incremental inputs.
            Last edited by MikeN; 11-27-2019, 02:17 PM.

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