Lion Precision’s CPL490 Capacitive Displacement Sensor measures position/displacement with 50 picometer precision or less. Relative to the noncontact sensor’s measurement range, that translates to a resolution value of less then seven parts-per-million even at 15 kHz bandwidth. “We are now able to measure changes in an object’s position when it moves less than the diameter of one of the molecules in the object,” says Don Martin, Lion Precision president. Previous models were capable of similar precision but only when high frequency components were filtered out of the measurement signal. The CPL490 can resolve target position changes of less then 100 picometers while objects are moving at 15 kHz. When bandwidth is increased to 50 kHz, a remarkably high frequency for capacitive sensors, the precision is still less than 0.3 nanometers.

Engineers, designers, and researchers needing incredibly precise measurements of changes in position of a moving object now have the tool they have been waiting for. High density hard-disk drives require spindles that turn with near zero amounts of error motion (wobble). Martin elaborates, “Disk drive spindles have gotten so good, it was difficult to measure the error with existing technology, but the industry demands ever higher rotary precision to continue packing more data on a disk.” Previous technology was incapable of seeing the tiny movements when the spindles were turning at operating speeds. The CPL490 has now opened a viewing window into the dynamic nano world enabling spindle manufacturers and designers to take the next step in precision. Many other industries including semiconductor and electron microscopy require measurement of position with similarly increasing precision. “Some new technologies can’t take the next step until they are given the ability to quantify these tiny movements. We are now able to provide that,” adds Martin.

The CPL490 is a new capacitive sensor module in Lion Precision’s Elite Series product line. For ease of setup, the device features a bar graph display indicating probe position within its calibrated range and an adjustable offset to “zero” the output . Bandwidth is selectable allowing the user to maximize the relationship between bandwidth and resolution for each application. The Elite Series is a modular system also offering signal processing and other capacitive sensor modules.

CPL490 Specifications (dependent on probe and range selection):
Output: ±10 VDC, single-ended or differential
Typical Resolution at 15 kHz: 0.0007%
Maximum Bandwidth: 50 kHz
Selectable Bandwidth: 1 kHz, 10 kHz, 15 kHz, 50 kHz
Linearity: <0.2%
Error Band: <0.3%
Maximum Drift: <0.02% F.S./°C