This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LDC2114EVM: can you have the inductance measurement absolute?

Part Number: LDC2114EVM
Other Parts Discussed in Thread: LDC2114

Hello,

Been playing with the eval kit for that sensor a while now but can't achieve functionailty i am after.

Basically if i move the target into sensor range after its powered i can get a certain trip position (a code value). if i then fix that target in that position & reset the power or go to config and back-> the code would get zeroed as this would be the new starting position (relative instead of absolute).

i am assuming this is due to the algorithms that work on the chip. Is there any setting for the registers to get out the absolute value of target position or inductance within the field?

how would one detect a button press if the button was pressed during the enabling the power to the chip ? therefore pressed button is referenced as base..

i worked with other sensors 1614/1314 which can kind of do what i want , but 2114 gives me superior range

Any help appreciated.

Kind regards,

Dariusz

  • Hello Dariusz,

    There's no way to turn off the baseline tracking algorithm in the LDC2114, which is what creates the relative digital outputs. 

    If the button was pressed while the LDC2114 powered on and made its first measurement, then you are correct that this metal position would be the initial baseline. There would be a large negative shift in the output codes when the button was released. When the output codes are negative, the baseline tracking will slowly shift the baseline to return the output codes to 0. Because negative values are generally undesirable, the Fast Tracking Factor can be enabled to speed up the baseline tracking. This would restore normal functionality to the button very quickly.

    If you need a true raw code output, you'll need to use either the LDC161x or the LDC131x devices. The sensing range is based both on the coil size and the resolution of the device. The LDC161x is our highest resolution LDC device (including the LDC2114), so with the same coil dimensions the LDC161x would be able to sense the farthest.

    Best Regards,