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ISO3082: Communication error

Part Number: ISO3082
Other Parts Discussed in Thread: ISO3088, ISO1430, ISO1450, ISO1410

Hi,

There is 2 questions about communication error(7MHz~11MHz)

1. Is there any issue in the schematic?

2. With adding 120Ohm resistor, can it support 32 nodes?

communication error waveform

Schematic

Adding 120Ohm for 32 nodes

Thanks.

  • Hi David,

    Thanks for reaching out.

    There is 2 questions about communication error(7MHz~11MHz)

    Regarding the waveform, could you please confirm what waveform is this? Is this a waveform at A with respect to GND2, B with respect to GND2 or the potential difference between A and B?
    Could you please also confirm the time-scale and the also the input signal applied?
    ISO3082 only supports about 200kbps (100kHz) of datarate and communication at 7-11MHz wouldn't be achievable with ISO3082. For support upto 20Mbps (10MHz), you can use ISO3088.

    1. Is there any issue in the schematic?

    I couldn't the values of components in the schematic clearly but it looks good. Please make sure the protection circuit on the bus is designed according to customer EMC requirements.

    2. With adding 120Ohm resistor, can it support 32 nodes?

    120Ω termination is needed to avoid reflections in transmission line for error free communications where there are multiple nodes on the bus that are located at farther locations. The schematic with 120Ω termination added looks good too. Yes, this will be able to support devices upto 32 nodes.

    I would also like to point out that ISO14xx family of isolated RS-485 transceivers is the newer generation family offering much superior overall performance against ISO308x family and is also pin-compatible. Hence I recommend customer to use this latest version. ISO1410 supports 500kbps, ISO1430 supports 12Mbps and ISO1450 supports 50Mbps. Thanks.


    Regards,
    Koteshwar Rao

  • Hi David,

    Please do help us with the information requested to be able to comment if there is anything wrong in the waveform. Thanks.


    Regards,
    Koteshwar Rao

  • Hi David,

    I am hoping that customer product is working fine and there are no further questions or clarifications needed.

    I will go ahead and mark this thread closed. If you do have further questions, please feel free to respond to this post or create a new post. Thanks.


    Regards,
    Koteshwar Rao

  • Hi Rao,

    Sorry for late response.

    Customer is in vacation. I'll contact you again for further support.

    Thanks.