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LDC1312: Practical Application of the LDC Series

HIROAKI YOSHIDA
Intellectual 290 points
Part Number: LDC1312
Other Parts Discussed in Thread: LDC0851EVM, , LDC0851, LDC1314, LDC1612, LDC1614

Thank you very much for your help.
I am on the verge of designing a proximity sensor using the LDC0851EVM.
Please let me know the following.

1. heat resistance temperature 180 degrees
The temperature of the metal plate where the proximity sensor (inductor coil) will be installed is up to 180°C. How should I design the LDC system?

1-1. Sensor structure
I would like to mold the board with inductor coil and LDC.
Do you have any examples of structures that can withstand 180°C?
It seems that the LDC series can be used at a maximum of 150°C. Should we separate the inductor coil and the LDC mounted board?

1-2. About the sensor shape
TI recommends spiral type sensors, but square or rectangular inductor coils are not suitable.
Compared to a spiral coil, a square or rectangular inductor coil has a smaller inductance, so how much will it affect the distance to the detected object?

2. About sensor separation
In the LDC1312/1314 datasheet, it is stated that the sensing range exceeds two coils.
Does this mean that two coils can be used separately?
In other words, by generating an inductive magnetic field from two inductor coils, it is interpreted that inductive sensing beyond one large inductor coil is possible, is that wrong?

Please refer to LDC1312 datasheet section 1. Features
3-1. "Remote sensor position of >20 cm for operation in harsh environments.
Is it correct to assume that the meaning of this sentence is the same as that described in 1.2 above?
Please let me know the specific usage.

3-2. "Supports compensation for environmental and age-related degradation in multiple channels.
What does this sentence mean? Does it mean that the detection distance adjustment volume included in the LDC0851EVM is unnecessary?
Does this mean that the detection distance adjustment volume included with the LDC0851EVM is unnecessary?

Regarding the device used in prototyping.
We would like to use the LDC0851, which offers more cost advantages when commercialized.
Please let me know which LDC device satisfies the above requirements.

Please let me know the LDC device that satisfies the above requirements. Thank you for your cooperation.

  • 0
    TI__Mastermind 33190 points

    Hiroaki,

    With respect to your questions:

    1. Heat resistance temperature 180 degrees
          As the data sheet says, the max temp for the LDC device is 150C, so your system will need to have separate sensor, with the device located in a remote, cooler place than the sensor.

    2. Sensor structure
      We can't provide any guidance on injection molding the sensor, other than to say we have worked with others that have used this approach.

    3. About the sensor shape
      The ability to detect an object depends on things other than the sensor inductance. It also depends on the sensor size, the target size and material, among other things.

    4. About sensor separation
      Could you please point out where you saw this statement in the data sheet? I doubt it means that you can use two separate coils.
      The most frequently quoted distance for sensing range is 40% of the sensing coil's diameter.

    5. (3-1)Please refer to LDC1312 datasheet section 1. Features
      I don't have the background on that statement. My guess is that it may be referring to a very large sensor and target, but that is just a guess.

    6. (3-2) Supports compensation for environmental and age-related degradation in multiple channels.
      I think it means that you can create system with reference coils that do not help with detection, but help the LDC device track changes to the environment, like temperature shifts.

    7. Regarding the device used in prototyping.
      Your local TI representative is the best bet to help you pick the best device for your application. 

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    Intellectual 290 points

    Mr. John.
    The intention of yesterday's inquiry 3.1 was to confirm whether the LDC1312/LDC1314, which are multi-channel inductance/digital converters
    I wanted to check if it is possible to detect a large metal object that cannot be detected by a single sensor, by sensing both sides of the metal object on the diagonal.

    I interpreted that it is possible to sense both sides of a large metal object, alternately and in turn, but is this correct?

    Also, the datasheet for LDC1612/LDC1614 only says
    (Not shown in the datasheet of LDC1312/LDC1314)
    1. Features
    "Sensing range exceeding the diameter of two coils".
    Please let me know what kind of usage is possible.

    Thank you very much for your cooperation.

  • 0 in reply to HIROAKI YOSHIDA
    TI__Mastermind 33190 points

    Hiroaki,

    We have no experience with an application which detects both sides of a large metal object. 

    My guess the statement "Sensing range exceeding the diameter of two coils" depends upon the higher 28b resolution of the LDC161x family, compared to the lower 12b resolution of the LDC131x family. If this is the goal of a system, its success would be very dependent on the requirements and the implementation.
    We do not have a reference design to offer which meets this goal.
    There may be some helpful information in one of our app notes Optimizing L Measurement Resolution for the LDC161x and LDC1101.

    Regards,
    John