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Old April 14th, 2016, 06:04 PM   #10
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Originally Posted by Geospark
The next step would be figuring out where in the controller tags the new data has mapped into via the scanner's 90 words, but that's for another day, and relatively simple work out.
Hard to add to the as-usual extremely thorough explanation by George, but just a quick trick that I've used before to find out where an unknown input is mapped to in a large DeviceNet array. Connect a switch or a sensor or something to one of the higher-numbered inputs, then go online and monitor the input data as the array of DINT's. Then toggle your switch/sensor on and off, and watch for one of the DINT values to be changing from zero to a very high number and back again. Then you can expand out that array and work out the individual inputs by watching the bits turn on and off.

The last time I did this was in trying to work out where a sensor is mapped to - and as luck (if you can call it luck) would have it, this particular sensor was wired to input zero of the card. So I was watching a running system with all sorts of flickering numbers, and the one I was looking for was changing from 30455 to 30456 and back again. About as difficult to find as one could ever hope for but of course, if you get to choose your input then you've got it easy!
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