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LDC1614: Inductive Sensor Resolution And Accuracy

Part Number: LDC1614
Other Parts Discussed in Thread: LDC0851

Hi, 

i'm working on rotational encoder(absolute or incremental doesn't matter so much) and the question is what is the best rotational encoder in the sense of ACCURACY and RESOLUTION that could be achieved with LDC devices.

as far as i have understood RESOLUTION depends on RATE OF CHANGE OF INDUCTANCE(or equivalently the resonance frequency) AS THE RELATIVE ANGLE BETWEEN TARGET AND SENSOR CHANGES, first of all is this absolutely correct or not and if yes, is there any formula or rule of thumb for resolution calculation, or are there any designs based on LDC that could achieve for example 18 bit resolution per cycle or not?

also about accuracy what i have understood is the best accuracy that could be achieved in any sensor is just the resolution and how much that accuracy is just determined by SNR, am i correct or not? and if yes i would deduce that there would be two important areas to stick on, 1st maximizing the resolution and 2nd noise isolating techniques.

  • Hello User,

    Thank you for considering LDC devices for your application. For rotary encoding applications we highly recommend the LDC0851 device. The LDC1614 parts can certainly be considered for rotary encoding application however the speed can be limited as there can be latency from the LDC1614 output through its I2C interface. For low speed application there is an app note and guideline that I can point you to. 1degree dial app note  

    In regards to resolution there is an app note that can provide you guidance. LDC resolution app note

    As you have browsed through the information let us know if you have any questions and I will assign this to our expert who can provide you further guidance. 

  • Thanks for the attention,

    first of all, is the only limitation of LDC1614 its latency? or there are some other stuff with it. because the speed doesn't affect just rotaary encoders it would be a concern in any moving application( no difference translational or rotational) and 2nd the link you have provided above LDC resolution app note seems not to be there anymore.

    thanks.

  • Hi,

    It would be better to go with LDC1614 if you are looking for the best resolution. This device has a wide sensor freq range from 1Khz to 10Mhz, 28-bit resolution and has a maximum sample rate of 4.1ksps. Please refer to the document LDC Device Selection Guide for the comparison of LDC devices which will help you decide the best device for your application. Here is the updated link for the  LDC resolution app note.

    Regards

    Sharath.