The MTI 2100 Fotonic Sensor Setup and Calibration Video shows the configuration and calibration of equipment that is used to make a high-voltage piezo-electric measurement with an MTI 2100 displacement meter and a Radiant high voltage displacement meter test fixture (HVDM). Also shown is a Radiant high voltage interface, a high-voltage amplifier, and a precision tester.
The bottom half of the Radiant HVDM has a fixed copper electrode that engages a connector. This connector applies a voltage signal from the tester’s output to the bottom electrode. The bottom reservoir can be filled with mineral oil to prevent arcing through the air around the sample.
The top half of the Radiant HVDM fixture also has a copper electrode. This electrode is free to move and allows for sampling a variety of thicknesses and detecting sample displacement. Inserting the sample close to the text fixture creates a sandwich with the electrodes and supports high voltage measurement.
Making a displacement measurement involves passing an MTI test wand through a stability arm and then through the center of the test fixture. Larger diameter test wands are held in place with a set screw. Shown in the video is a one-sixteenth hex screw adjusted with a one-sixteenth hex wrench.
A friction sleeve is inserted in the hole and remains in place. The stability arm attaches to the micrometer post blocked with the hex screw. This micrometer post is used to make fine adjustments to the detector’s position. The stability arm and the micrometer setting can be locked in place with a ring at the head of the micrometer.
To begin calibration, it is necessary to establish the linear relationship between the displacement that the MTI 2100 will detect and a zero voltage reference. There are two plug-in ports. Each allows a different plug-in and represents a channel on the MTI 2100 displacement meter. The left plug-in is channel one. There is a label on the side of this plug-in with the scaling terms that are needed for conversion.
In the software, microns per volt are entered and a meaningful name is assigned to the advanced piezo task. The voltage is set and the high-voltage amplifier is added. Next, the MTI 2100 displacement meter is added. The value is negative because positive displacement of the sample reduces the distance between the reflective surface of the electrode and the test.
Execution involves reinserting the plug-in and making sure that it’s firmly seated around the MTI 2100. When the setup for the displacement is complete, the software displays procedures. Note that MTI’s plug-ins operate in two ranges. Range two is for large-scale displacement and is not used here. Range one is ten times more precise, so it’s important for this exercise.
As the MTI 2100 Fotonic Sensor Setup and Calibration Video shows, the high-voltage high signal from the MTI 2100 is sent to the Radiant HVDM. The front panel of the MTI 2100 shows a rough maximum. The micrometer is adjusted until a true maximum is found. The ring is then locked-in. The bipolar voltage waveform that is applied to the sample will displace in both directions.