LINEPULS & LINECOD catalogue 2016 in English

LINEPULS • LINECOD
Technical information
www.lika.biz
The terms “accuracy” and “repeatability” are in straight relation between each other and are
often used as synonyms. Actually, their meaning is very different.
Accuracy
1 High accuracy,
high repeatability
2 High accuracy,
low repeatability
3 Low accuracy,
high repeatability
4 Low accuracy,
low repeatability
As you can easily understand from the Figures, a measurement system can provide high accuracy
but low repeatability (2), high repeatability but low accuracy (3), neither (4), or both (1).
Many factors can affect both accuracy and repeatability:
• the characteristics of the magnetic tape;
• the characteristics of the sensor;
• the characteristics of the overall application where the measurement system is integrated
(mechanical alignment, etc.);
• the environmental conditions.
The accuracy of the magnetic tape is indicated by μm/m in the datasheets.
The accuracy value represents the maximum deviation of inaccuracy inside any section of 1 m
of the measurement range. The accuracy class is listed as ± xx μm, where xx = number of μm/m.
Since most of the tapes can be supplied with different accuracy classes, it has to be indicated
under the option ACCURACY CLASS in the order code.
The system (sensor) accuracy refers to the error within the single pole and depends mainly
on the sensing elements and the electronics. It is expressed in μm.
Repeatability is the ability of the measurement system to provide consistent information
under the same -unchanged- conditions or under different -changed- conditions.
The standard deviation is expressed in increments.
Repeatability
Most of Lika Electronic linear encoders are equipped with LEDs intended for diagnostic purposes.
They are meant to show visually the operating or fault status of the device and the
interface as well as to help the user during installation and set up.
They also signal the activation of Reference and Limit Switch marks, when available.
Diagnostic LEDs
Specific models include additional rubber cleaning wipers to be mounted on the sensing
head (order code KIT WIPERS). They are designed for debris removal from the magnetic tape
surface ensuring a clear path of motion.
Cleaning wipers
15