Welcome to POSICoder's FAQ-page

A POSICoder is a differential transformer integrated on a chip. The copper strips on a scale or disc or the teeth of a gear modulate the coupling between the primary and secondary windings. A more detailed description can be found on the Technology page.

Yes, the sensing principle in a POSIC encoder is a differential transformer. The primary coil generates a magnetic field, the secondary coils measure the magnetic field, which is modulated by the scale or codewheel. This mechanism works perfectly when the codewheel or scale is not moving.

The maximum speed is set by the parameter Max Speed BB as listed in the corresponding table in the Section “Ordering Code” at the end of each datasheet. For linear encoders it may vary from 20 mm/s to 60 m/s and for rotary encoders from 5 to 25'000 RPM.

The time-delay depends mainly on the setting of the parameter Max Speed BB as listed in the corresponding table in the Section “Ordering Code” at the end of each datasheet.

For BB = 01 to 09, the delay is the time-constant of a first-order filter with adjustable bandwidth and may vary from 50 us to 25 ms.

For BB = 20 – 23, the position-filter is a second order filter with zero delay at constant speed.

Yes! Scales and discs are straightforward PCBs (Printed Circuit Boards) with copper strips on the frontside and a plain copper layer on the backside that acts as a screen against metal objects behind the scale or disc. The PCB consists of 0.6 mm FR-4 (or thicker), 35 um copper and a protective layer (typically solder mask or nickel/gold finish). Detailed information:

The pitch or period-length is the center-to-center distance between two copper strips. This should be between 1.2 and 1.4 mm and is explained in more detail in the Application Note AN018

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Yes, you can download POPSICoder's RoHS and REACH declaration here:

The hardware in the Evaluation Kit will work with POSICoder and POSIC encoders. However, the software is different. For POSICoder, the POSICoder Software must be used, whereas for POSIC, the ASSIST Software must be used. Both softwares can be installed on the same PC, but only one software can be activated at the same time.

The POSIC encoder is a differential transformer. The primary coil generates a high-frequency magnetic field (1 – 2 MHz) and measures this field back using the secondary coils. Perturbations below 1 MHz are filtered out. As most magnetic fields from magnets, motors, drives etc are well below 1 MHz, these magnetic fields do not influence the encoder. In addition, the secondary coils in the encoder are arranged in a differential configuration, so that a magnetic field acting on two differential measurement coils is eliminated.

So yes, POSICoders are immune against magnetic fields.