A new powerful generation of linear and angular measuring encoders – unlike any optical or magnetic encoder, has been developed based on our AMOSIN® Inductive technology, where high-precision is achieved by scanning stainless steel photolithographically etched structures with sophisticated inductive sensors and processing the signals with proprietary integrated electronics (ASIC).
The AMOSIN® length measuring encoders can be supplied as open non-contact encoder or as a non-contact guided linear guideway rail as an alternative to encapsulated (extrusion) optical encoders.
The angle measurement encoders are Ring Scales with open hollow large bore thru holes and have non-contact inductive scanning of the graduation pattern ring with no coupling or mechanical connection, for easier application to rotary feedback applications.
The AMOSIN® encoders operate on the principle of a transformer with a moving reluctance. The mutual inductance of the primary and secondary windings of a transformer changes depending on the relative position with respect to the core. The AMOSIN® system (Fig. 1) consists of a planar micro-coil structure and a measurement scale. The coil structure with a plurality of coils aligned in the direction of measurement (individual sets of micro-coils for Sine and Cosine), is incorporated on a substrate with micro-multi-layer flex circuit technology. The scale is a stainless steel scale with a high-precision photolithographic etched periodic graduation (eg λ = 1000 microns) with variable reluctance.
The total measurement error of a measuring encoder is caused by the errors listed below:
- Graduation Pattern Accuracy – Determined by the quality of the measuring scale.
- Accuracy within the Graduation Pitch – Determined primarily by the quality of the sensor signal sensing the graduation pattern pitch, and the quality of the evaluation electronics of the scanning head.
- In addition, for the measuring encoders with output interface 1 Vpp to consider the following:
- Accuracy of analog / digital conversion in the input stage of the subsequent electronics (control side).
- Coupling of noise on the encoder output signal in the transmission of the sine wave signals to the subsequent electronics.
Each linear/angular scale is calibrated on a test bench and has a test certificate, which indicates the accuracy class meets the customer specified requirement. Optionally, an accuracy chart (measured under ideal assembly conditions) can be supplied.