问什么是磁栅编码器?

。

Measuring standardHEIDENHAIN encoders incorporatemeasuring standards of periodic structuresknown as graduations.Magnetic encoders use a graduation carrierof magnetizable steel alloy. A write headapplies strong local magnetic fi elds indifferent directions, so that a graduationconsisting of north poles and south poles isformed with a signal period of 400 μm(MAGNODUR process). Due to the shortdistance of effect of electromagneticinteraction, and the very narrow scanninggaps required, fi ner magnetic graduationsare not practical.Magnetoresistive scanning principleMeasuring standardScanningreticleMagnetoresistive sensors for B+ and B– not shownMagnetic scanningThe permanently magnetic MAGNODURgraduation is scanned by magnetoresistivesensors, whose resistances change inresponse to a magnetic fi eld. When avoltage is applied to the sensor and thescale drum moves relative to the scanninghead, the fl owing current is modulatedaccording to the magnetic fi eld.The special geometric arrangement of theresistive sensors and the manufacture ofthe sensors on glass substrates ensure ahigh signal quality. In addition, the largescanning surface allows the signals to befi ltered for harmonic waves. These areprerequisites for minimizing position errorswithin one signal period.A structure on a separate track produces areference mark signal. This makes itpossible to assign this absolute positionvalue to exactly one measuring step.Magnetoresistive scanning is used primarilyfor comparatively low-accuracy applications,or for applications where the machinedparts are relatively small compared to thescale drum.Incremental measuring methodWith the incremental measuring method,the graduation consists of a periodicgrating structure. The position informationis obtained by counting the individualincrements (measuring steps) from somepoint of origin. The shaft speed isdetermined through mathematic derivationof the change in position over time.Since an absolute reference is required toascertain positions, the scale drums areprovided with an additional track that bearsa reference mark. The absolute position onthe scale, established by the referencemark, is gated with exactly one measuringstep. The reference mark must thereforebe scanned to establish an absolutereference or to fi nd the last selecteddatum.

是在园型磁铁表面充了多个S,N极，配合检测元件（霍尔）组成的。

磁栅式传感器（ magnetic grating transducer ）利用磁栅与磁头的磁作用进行测量的位移传感器。它是一种新型的数字式传感器，成本较低且便于安装和使用。精度较高,可达±0.01毫米／米，分辨率为1～5微米。可有直线，角度编码器（传感器）原理类此磁带录音，录上等距磁信号，由磁头读出，广泛用于机床等的位置测量。