MICRONOR AG
MR340-1 DIN Rail Module Controller
Page 66 of 74
7.
MR340 Theory of Operation
In this section, we explain the inner workings of the MR340 series fiber optic incremental
encoder system.
The system incorporates an all-optical design per Micronor’s US Patent 7,196,320. There are
no electronics in the sensor whatsoever.
The controller sends light of two distinct different colors (850nm and 980nm) through the
transmit fiber. Within the sensor the two colors are split up into two distinct collimated light
beams. Each beam passes through a spatial filter probing the A and he B track on the sensor
wheel. The light of each beam is now modulated with the 90° phase shift based on the turning
direction of sensor wheel. The modulated light is coupled back into the optical receive fiber
guiding the light back to the receiver in the controller module.
The two colors of light are returned to the controller, converted back into an electrical signal,
amplified to a known level, and then output as A/B quadrature signals.
Fiber optics will guide the light efficiently and over large distances. However the light
amplitude is not guaranteed to stay stable at all. The microprocessor main role is to supervise
the optical power levels and make the necessary adjustments when the light levels drift.
Figure 25. Block Diagram of MR340-1 Controller