Check the data sheet. I believe that the correct value of resistance is 4.7k ohms. Whenever you want to run more than a certain number of sensors on one line, it is more reliable to pull the line high with a transistor if you are wiring them in parasite power mode. If the sensors are wired with a separate power wire, the pull-up transistor is not necessary.
Last edited by jeff5may; 08-07-17 at 10:15 PM..
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