LVDT Calibration

[S.G1.]

Hi ,

im trying to configure my SCXI 1540 Module w/1315 terminal block card for excitation voltage 3 Vrms and frequency 2.5Khz using Max

I have LabVIEW Express 7.1 PDS - SCXI-1000 Chassiss - along with PCI-6254 is attached to the 1540 card.
MAX says it recognizes all the cards in the chassiss. The LVDT Probe when connected to the SCXI 1540 does not show any change in values even when the probe is moved .
The probe has been checked individually as well as the the excitation signal on the SCXI 1540 module channel has been checked on the CRO.(Though in MAX we have set the excitation frequency to 2.5KHz it shows  a frequency of 7.8 KHz).

The PCI 6254 has two connector inputs Connector0 is from the SCXI  and Connector1 is from  SCB 68 module (Digital signals from the client main panel are routed to the SCB68 terminal block).

Plz Help

Subhash

[Paul_C.]

Hi Subhash,

The SCXI 1540 can be sometimes difficult to calibrate.  I found a great article that may help troubleshoot the problem found here.  In addition, have you tried to verify if modifying the frequency in MAX modifies the actual frequency that you see through the CRO.  This might help you modify the settings to achieve the 2.5 KHz frequency.  It might help if you could provide the specifications of the LVDT probe that you are using to make sure that it meets the requirements.  I'm also assuming that you are using a LVDT position task.  Can you verify this?

Regards,
Paul C.

[S.G1.]

Thank you paul for sending me the details for the LVDT trouble-shooting .

The LVDT specifications are as follows

Make - MERCER

Modal number - 03236490

Wire Type - 4 wire.

It would be of great heLp to me if I can get the 4 wire connection diagram of this LVDT.

The application is position based as you have assumed earlier

[Chris_D]

A 4-wire connection diagram can be found in the SCXI-1540 product manual under Chapter 2 Connecting Signals. Also, were you able to perform any of the troubleshooting steps that Paul suggested? What were the results of those tests?

Product Manual: SCXI-1540 8-Channel LVDT Signal Conditioner
http://www.ni.com/pdf/manuals/372581b.pdf