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Is this safe -- Probotix opto-isolated relay?

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    Is this safe -- Probotix opto-isolated relay?

    I read with interest the dialog on protecting the ADIO digital output from relay coil voltage surges (thanks hult and catsandi). It seemed to me an opto-isolated relay would be the solution. Probotix offers their RBX-1 3-channel board for $33. The three optical inputs are 5VDC with common ground which seems to be a good match with the ADIO.

    So would this be a safe relay driver solution?

    I'm also concerned by the ADIO's common ground which is connected to the serial ground which is connected to the computer's serial ground which probably is connected to the computer's power ground which is connected to main's ground. Even though my computer has available serial ports, I think it might be better if I used a Serial-to-USB interface to isolate the ADIO's common ground.

    Am I being too cautious or is this a worthwhile protection measure?

    Thanks for assistance.

    In an optically isolated solid state relay there is no electrical connection between the low voltage input and the high voltage output. I have some experience with similar devices and I've never seen a failure mode where the input has been exposed to higher voltages. It should therefore be safe to use.
    I'm not sure a Serial/USB interface is going to add any additional protection as it too will have a ground on both sides at the same potential as that of the ADIO.
    Real courage is not securing your Wi-Fi network.


      Use of optos with ADIO

      In ANY control environment that you want to be robust and tolerate "real world" transients (like static and lightning induced transients that are picked up by the sensor wiring) you should buffer any IO device (where possible) with opto-isolators and/or relays. I have used Industrologic's RIO8 to provide isolated relay outputs and their UOB8 to buffer the digital inputs If you need to isolate all the sensor grounds, their UOB4 has 4 completely separate isolators so there is no interaction with real-world grounds. These are top-notch quality products and frankly, you couldn't build them (time and materials) for the little money they charge for them. Buffering the analog inputs presents a bit of a challenge. Still working on that one....