MME-1000 LVDT Signal Conditioner Calibration Procedure

TE Connectivity Macro Sensors EAZY-CAL MME-1000 = LVDT Signal Conditioner Calibration Procedure

With the Eazy-Cal now fully warmed up, we are ready to initiate the calibration procedure. This is accomplished by simultaneously depressing and holding the zero and full-scale buttons for three seconds or until the red opt cal LED indicator lamp starts to blink, signifying that the calibration mode has been entered.

Now that we have entered calibration mode, you will notice that the plus-to-minus LED lamps above and below the null LED indicator lamp will flash on and off as the LVDT coil is passed up and down the core. These lamps provide a visual position indication of the coil relative to the core. When perfectly centered, the null LED indicator lamp will be steadily illuminated, meaning that the LVDT is at the center of its total stroke or at null. We then position the coil in the test fixture as closely as possible to null and lock the coil in place.

Next, we adjust the digital micrometer head until the null LED indicator lamp is steadily illuminated. Being at null, we now reset the digital micrometer readout to 0. Next, we’ll displace the LVDT core by negative 0.5 inches using the digital micrometer head and readout. This will take us to the negative end or 0-inch position of the LVDT stroke range. In relation to the Eazy-Cal, this will be the 0 volt DC output position.

Next, we enter the zero calibration point into the Eazy-Cal by momentarily pressing the zero push button. The three positional indicator lights on the front panel will then briefly sequence, providing positive feedback that the zero points have been stored. The positive position of an LED lamp will then illuminate. We now reset the digital micrometer readout to 0.

Next, we displace the LVDT by plus 1.0 inches. When the final position has been reached, we enter the full-scale calibration point into the Eazy-Cal by momentarily pressing the full-scale push button. The positive position indicator lamp will turn off and the opt cal LED lamp will become solidly lit, indicating the calibration has been successfully completed and the normal operation mode is engaged.

We now observe that the output voltage of the Eazy-Cal as displayed on the DVM is plus 10.0 volts DC, with plus 10.00 volts DC being nominal for the plus 1.0 in stroke position. We now displace the LVDT back to the plus 0.5-inch position and we observe the output to be plus 4.99 volts DC with plus 5.00 volts DC being nominal.

Finally, we displace the LVDT back to the 0-inch position and we observe the output to be 0.00 volts DC. Calibration has now been successfully completed and the Eazy-Cal is ready for normal operation.