How to measure, LVDT primary secondary RMS in U3-HV?

7 posts / 0 new

Tue, 07/11/2017 - 02:19

Ashif

My aim is to measure LVDT primary voltages attached the Layout( AC RMS (+/-0.7 to +/-10V) with 3.2KHz) , I have purchased one U3-HV. I need 4 similar channels, i.e 2 primary and 2 secondary( please check attachment ) Since Sampling of high frequency is expensive operation, We have decided to convert LVDT primary and Secondary to DC level and feed to Labjack for measurement of voltage.

Our Primary Voltage to LVDT is AC RMS (+/-0.7 to +/-10V) and Secondary voltage of LVDT is AC RMS (+/-0.7 to +/-5V) with 3.2KHz.

Can you update me the best approach to measure this 4 differential voltages with best budget possible?

Please note that, LVDT AC/RMS voltage signal is feed from the Servo control board, does it cause any issue of common mode signal while measuring this 4 channels?

Thanks

Ashif

+917760889950

File Attachment:

ServoBoard.png

Wed, 07/12/2017 - 11:33

LabJack Support

Are you saying that you want

Are you saying that you want to add some signal conditioning circuitry to the area within the red box in your drawing? You want to add circuitry that converts 4 3.2 kHz AC signals to DC values that can be measured by a U3-HV?

Wed, 07/12/2017 - 22:01

Ashif

Are you saying that you want

Are you saying that you want to add some signal conditioning circuitry to the area within the red box in your drawing?

>>>>Yes, I need some signal conditioner circuitry.

You want to add circuitry that converts 4 3.2 kHz AC signals to DC values that can be measured by a U3-HV?

>>>>Yes, you are right, I need converter and read the voltage in U3-HV ( My prefered programming language is C++).

Thanks

Ashif

Thu, 07/13/2017 - 12:38

greg.lemunyan

What about using a RMS

What about using a RMS converter such as http://www.linear.com/product/LTC1967

Thu, 07/13/2017 - 16:14

LabJack Support

Yes, the LTC1967 might be a

Yes, the LTC1967 might be a slick solution. The unknown though is whether you can use 4 of these in your system without individual channel-to-channel isolation. That is, powering all 4 from the same VS/GND supply from the U3, and connecting the output signals to 4 (or maybe 8) non-isolated analog inputs on the U3. The answer to that is going to require talking to the manufacturers of the servocontroller and the control valve.

Mon, 07/17/2017 - 01:08

Analog input

My analog input voltage range

My analog input voltage range is+/-0.1 ,+/-1V and +/-5V both differential input as well as single ended input, i want used both condition same circuits without any change in the board.

kindly advice the signal conditioner circuits .

Thanks & Regards

Chockkalingam M

Tue, 07/18/2017 - 00:42

Ashif

@Chockkalingam

LTC1967 IC integration is not done, mostly it may takes few weeks. Will update you once it has progress.

Thanks, Ashif