LVDT with one secondary coil

James Boehm

Prodigy 70 points

Other Parts Discussed in Thread: LDC1612, LDC1101

I would like to know if it is possible to create an LVDT with only one secondary coil?

over 8 years ago

0 Ben Kasemsadeh over 8 years ago

TI__Genius 13650 points

Hello James,

something similar has been done here: http://www.ti.com/lit/an/snoa931/snoa931.pdf

0 James Boehm over 8 years ago in reply to Ben Kasemsadeh

Prodigy 70 points

Thank you Ben for your reply. I am trying to simplify what we make now. The primary coil is divided in two coils running in series and the secondary is in two different locations with it's own primary. We use small pieces of metal to balance the coils which can be time consuming. What I would like it so be able to eliminate one of the secondary coils and maybe use a circuit or chip to act as the secondary coil. Is there such a thing?

James

0 Ben Kasemsadeh over 8 years ago in reply to James Boehm

TI__Genius 13650 points

Hello James,
inductive sensors such as the LDC1612 are not LVDTs. They can also be used to translate linear position into an output code, but their operation is different from LVDTs. This can be achieved with a single coil, as shown in the linear position sensing apps note. For improved measurement accuracy, it is also possible to add a second coil and take a differential measurement. The LDC1612 has two channels, so two coils can be connected to it.

0 James Boehm over 8 years ago in reply to Ben Kasemsadeh

Prodigy 70 points

Hi Ben,

If we use the LDC1101 could we connect an DAC with I2C to get an analog reading out or do we need to add an MCU to the mix?

0 Ben Kasemsadeh over 8 years ago in reply to James Boehm

TI__Genius 13650 points

Hello James,

an MCU is required to configure the device and read the data. I recommend looking at an MCU with integrated DAC if you need an analog output.

0 James Boehm over 8 years ago in reply to Ben Kasemsadeh

Prodigy 70 points

Hi Ben,

Thank you for your information. I would need a MCU with integrated DAC for the LDC10101 as well as voltage regulator that will drop from 12VDC to the voltage that is needed. These will need to be mounted on a circuit board that would be about 1 inch round. What MCU would you recommend?

Regards,

James

0 Ben Kasemsadeh over 8 years ago in reply to James Boehm

TI__Genius 13650 points

Hello James,

for questions on low-power MCU selection, please post your requirements in the MSP forum; my colleagues from the microcontroller team will assist: http://e2e.ti.com/support/microcontrollers/msp430/

0 James Boehm over 8 years ago in reply to Ben Kasemsadeh

Prodigy 70 points

Ben,

Can the component circuit board that has the LDC1101 chip be stacked on top of the circuit board coil? If so, how close can they be before interfering with readings.

Also, the capacitor for the coil, does it have to be next to the coil or can it be with the LDC1101 chip if the LDC1101 chip is in close proximity to the coil?

We are looking to use this as analog out with a reading of 0V - 5V. What is the resolution output? Can it detect less than .003" change?

Sensors

Sensors forum

LVDT with one secondary coil