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neil-sarkar / MEMS_AFM_MCU_CTRL

MCU code for ADUC7122
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Z-offset feed forward correction #5

Open ushardul opened 10 years ago

ushardul commented 10 years ago

During a line scan, thermal (electrical?) coupling between the lateral actuators and the z-actuator causes the z-actuator measurement to deviate causing some error in the topology scan. Use feed forward correction to correct for the error in the z-actuator measurement by driving the z-actuator with a higher voltage.

ushardul commented 10 years ago

No noticeable coupling testing with 1k Pheasant devices (or it is less than 1 LSB) doing a full sweep up to maximum lateral actuator voltages (3.3 V).

neil-sarkar commented 10 years ago

There may not be any DC bias on the z-actuator while we're looking for this coupling. I suggest we apply 250mV to the Z actuator at the beginning of the calibration process so that there is enough current through the 1ohm resistor to get a meaningful measure of coupling from the lateral actuators.