This Technical Paper is an overview of the accuracy capabilities of the Veratus™ linear encoder system with Verapath™ optical technology on VILT linear tape scale.
This Technical Paper is an overview of the accuracy capabilities of the Veratus™ linear encoder system with Verapath™ optical technology on VILT linear tape scale.
Verapath™ optical technology incorporates LED based diffractive optics, a large detector array and advanced signal processing to provide excellent accuracy performance which is insensitive to grating flatness variation and scale contamination.
Linear encoder accuracy has three major error components:
1. Slope
2. Linearity
3. Sub-Divisional Error (SDE)
The VeraPath™ optical system uses a collimated, low coherence LED light source to illuminate the multi-track pattern on VILT scales. By using a low coherence light source, foreign items on the scale such as contamination or scratches do not create interference patterns of their own which would produce undesirable modulation on the detector. With VeraPath™ filtering optics, the 20μm period interference fringes are virtually the only influence on the final encoder signal.
Additionally, the detector’s interleaved photodiode array samples and averages the fringes over a wide area. The combination of this optical filtering, averaging, and VeraPath™ advanced signal processing produces excellent signal fidelity resulting in high accuracy measurements.
Veratus Series optical encoders deliver the high accuracy made possible by VeraPath optical technology. Veratus is in a class by itself when taking into consideration that all of the electronics are miniaturized and contained inside the encoder sensor. No external signal processing is required and there are no bulky signal processing or interpolation modules at the other end of the cable. Veratus offers truly world class accuracy on metal tape scale in a small, low power consumption, light-weight package.
Please contact Celera Motion Applications Engineering group with any questions regarding Veratus encoders or VeraPath technology.
Note: All accuracy data presented was collected using a standard Veratus encoder and VILT. The reference measuring system was a NIST traceable laser interferometer in a temperature, humidity, and vibration controlled environment.