• Resolved

LDC1614EVM: Inductance measurement issues with magnet in solenoid.

Part Number: LDC1614EVM

I move a long skinny cylindrical magnet through a solenoid coil. I have this coil attached to LDC1614EVM CH2 port.

I move the magnet 1 inch back and forth using a stepper motor stage. (one end of magnet is always inside the coil, the other end is always outside the solenoid)

I stream data to a file using the OneUI application.

The data is fairly linear, BUT, has consistent hiccups in the reading in the middle of travel. (as shown in this graph)

Any idea what could be causing these hiccups. (I want to use the sensor for linear distance, but hiccups would be a problem for me)

Thanks,

    Craig

  • Hello Craig,
    The hiccups you mention look to be systematic and repeatable in the same locations which leads me to believe it is related to something mechanical in the system. Have you confirmed that your stepper motor is not the culprit and that it actually does have a linear response? I've seen stepper motors sometimes overshoot the target and correct itself. For debugging purposes, you could try speed it up to see if the problem becomes more pronounced or try slowing it down to see if smooths out. Also, if you slow it down you can check each increment independently to see if there is a transient behavior caused by the stepper motor or if the response is actually linear.

    Regards,

    Luke

  • In reply to Luke LaPointe:

    O.K. It looks like I had some bad configuration data, after playing with configuration registers, the graph is now smooth, and
    I have much better resolution. I think the OneUI program should give much better explanations of the settings.