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I have 3 XBee SMT Grove Development Boards. I configured two of them as coordinator and endnode respectively. Note that the end node is not connected to any intelligent computer via its serial interface. It is simply powered on and is configured to read an analog sample at regular intervals and transmit it to the coordinator.

My intension is to connect an analog sensor (example: Rotary angle sensor) and transmit the knob position at regular intervals to the coordinator (using the IO data sample indicator frame).

I connected the sensor to the AD3 slot of the end node. And end node reads a sample of data and successfully sends this value to the coordinator at regular intervals. However I noticed that for a position of approximately 0-150 degrees, the IO sample value as received at the coordinator seems to be (21-1023). Meaning, the value changes according to the knob position. But when I move the knob position further (the supported rotation range by the sensor is 0-300 degrees), from 150-300 degrees, I notice the value always remains constant(1023).

I know that 2 bytes of analog samples can be transmitted via this frame. And the IO sample of the sensor is also 2 bytes. So I am wondering why the value remains the same for half the position of the rotary where as for the first half it changes as expected ? Please note that the sensor is already tested on a Grove Pi+ shield on a Raspberry Pi for correctness using the example code. It works perfectly throughout the whole range.

Thank you all for your time.

lightsunray
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