openinverter forum

Hi,

The motor i am using has a RMB29AC01SS1 encoder (https://eveurope.eu/wp-content/uploads/rmb29d01.pdf) and i am using it with a Auris inverter with Damians block 4 board.

The encoder gives a sine wave with an output of 2.45V to 3.55V, which is obviously higher than the range of the inputs on the board (3.3V). To reduce this I have added 50k resistors across the 1nF filter caps. This gives me a voltage range at the ADC input of 2 - 2.9V.

I have set the sincosofs to 3040 (2.45V) which should be the midpoint of the signal. However when I spin the motor, I see a angle between 100 to 350 degress. I cannot seem to get a reading below 100 degrees.

Am i doing something wrong? Should this encoder work with this setup

FYI - Running V5.05 FOC

100 to 350 - interesting, so the high side is close but the low side is not.
You may need some sort of op amp prescaling to get a 0-3.3v signal.
I believe sincosofs was intended to handle rather small deviations (resistor tolerance level)and not to adjust the 0-degree point (so 0 degrees is still 0 volts? not quite sure how the logic works there.)

According to datasheet you've provided you should see 1.9V .. 4.1V on the sine output. If you put resistor on the line, it should be lower.
Probably your offset is not in the middle of sine amplitudes. On the screenshot of the oscilloscope you have set offset of -2V.
Probably you are adding this offset from oscilloscope to the value of "sincosofs".