![]() ![]() With the problems associated with analog isolators, this would push me toward using an external ADC and serial bus isolators. My pref, though, would be to keep the arduino on the computer side, then you won't need to worry about clock noise spreading across your nice clean isolated ground. Digital isolation is cheaper and easier than analog.Įach method will have advantages and disadvantages. 820-40(b)(1)(1996 edition) requires that the cable shield ground connection as it enters the house be made to the existing building grounding electrode system, i.e. are doing everything possible to minimize these loops. Or, you can use a serial bus isolator, like the ADUM1250 I2C isolator to bring the data to your arduino using digital means, which has the advantage of being useful on a bidirectional bus like I2C, if your ADC is of that ilk. 1 Actually, conscientious cable installers who truly follow Article 820 of the N.E.C. ![]() The easiest way to do it, short of a USB isolator, is to power the arduino off-chip, put an external ADC in your system, and use digital isolators, like your 6N137. What is Ground Loop Noise and what Causes it Understanding the concept of ground loop noise is key to understanding the need for a ground loop isolator. There may even be some that provide the isolated power. You can construct your ground loop isolator all by yourself by using a few tools and materials that are available at your local hardware shop. You can also use ISOLATION AMPLIFIERS ( ) to the same effect, and they're likely easier to use. Such things can be tricky to use, and will require op amps on both sides of your isolation. The next way to go would be to leave your arduino under USB power, provide an isolated power supply for your analog side, and use an ANALOG Isolator to bring the signal to the ADC on your arduino.Īn inexpensive analog isolater is the HCNR201. ![]() That device actually produces an Isolated power source that can provide 100mA of current (though I'm not sure that's enough for the Arduino - you'd have to look it up) The easy way is to use a USB isolator, like the Adafruit implementation at The TI selection matrix for such devices is at Digital optocouplers are important for some of the designs that follow, but they don't supply power, which you can generate off of a USB bus with a DC/DC converter with isolation. There are a number of approaches, going from expensive and easy, to cheap and more complicated.įirst off, a 6N137 is an Optocoupler, and not a source of isolated power. ![]()
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