Permanently stable measured values in original signal quality

Exposed linear encoders from HEIDENHAIN are used wherever there is a need for positioning of extremely high accuracy or for a precisely defined motion, for which they always provide very stable scanning signals. However, contamination on the measuring standard or on the scanning reticle can impair these scanning signals. To ensure that these high accuracy requirements can be fulfilled over the encoders’ entire life cycle, HEIDENHAIN has developed a new signal processing ASIC. It first finds application in the new generation of exposed linear encoders with incremental position value acquisition.

The new HEIDENHAIN signal processing ASIC permanently monitors the scanning signal. When scanning signals are subjected to external influences, contamination of the measuring standard, for example, which change the signal, then the new signal processing ASIC practically completely compensates these signal changes and restores the original signal.

If the signal amplitude decreases, the signal processing ASIC corrects this by increasing the LED current. The ensuing increase in the LED light intensity hardly at all affects the noise level in the scanning signals, even when there is a high degree of signal stabilization–quite contrary to systems in which the gain is made in the signal path, which increases the noise level.

The signal amplitude stays nearly constant at 1 V_PP. Even if the ASIC’s control limit were exceeded due to extremely heavy contamination, it would not result in an abrupt signal failure. Instead, the signal amplitude would only decrease slowly with increasing contamination.

But the new signal processing ASIC not only stabilizes the signal amplitude. It also ensures that the signal retains its original, ideal form. In this way it keeps the interpolation deviation very small, even when the measuring standard and scanning reticle are contaminated. Thus the control loop receives highly accurate position information permanently and reliably.