New capacitive single-channel controller for displacement measurement

Three new capacitive controllers for capacitive displacement sensors from Micro-Epsilon look ideal for addressing a wide range of applications. These new electronic units replace the existing capaNCDT 620 Series to form a new single-channel solution from the company.

The capaNCDT 6300 can justifiably be described as "high resolution". It achieves a resolution down to two nanometers and operates with a cut-off frequency of 8kHz. A distance of 1m is possible between the sensor and the electronic unit.
If the application requires a larger separation between the sensor and controller, this can be achieved through the capaNCDT 6310 Series. This electronic unit possesses an external preamplifier, which extends the distance between the sensor and evaluation unit to a maximum of 11m. Also, where installation space is tight, the sensor can be used with the compact preamplifier.

Potential applications for the two new controllers are anywhere where extreme accuracy is required. An example here is the alignment of the optical system when exposing wafers, where every nanometre counts, or for measuring unbalanced mass on dental drills.

The capaNCDT 6350 Controller can also be described as "fast". It has a cut-off frequency of 50kHz and can therefore also detect fast movements. With this device, the maximum distance from the sensor to the electronic unit is 2m. An extension of this distance is not possible. Instead, it can be linearised to special measurement objects so that the precision achieved increases still further. This controller is particularly suitable for fast processes. For example, the vibration of electrodes during ultrasonic welding – also known as sonotrodes – can be determined, which causes the welding surfaces on plastics to melt using very small oscillations.

As outputs, all the evaluation units provide a current and a voltage signal.

All three series offer the usual advantages from Micro-Epsilon. For example, the sensors can also be replaced without recalibration of the evaluation unit. The sensors are based on the principle of the guard ring capacitor and offer particularly high measurement accuracy and linearity. The capaNCDT 6300 makes use of an analogue circuit and is therefore able to achieve such high precision. Due to the high speed, a digital signal processor is used with the capaNCDT 6350, which makes it possible to obtain such high cut-off frequencies.