Beckhoff EL5032, Документация

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Basics of EnDat 2.2 technology
EL5032, EL5032-0090 28 Version: 2.4
4 Basics of EnDat 2.2 technology
Basic information on the technological field of "EnDat interface" is to be given below. It is up to users to
check to what extent this information refers to their application.
4.1 EnDat 2.2 - Bidirectional interface for position
measuring devices
Digital drive systems and position control loops with position measuring devices for data sampling require
measuring equipment offering fast data transfer with high transmission integrity.
In addition, further data such as drive-specific characteristic values, correction tables etc. should be
provided. To ensure high system reliability, the measuring devices should be integrated in error detection
routines and offer diagnostic capabilities.
The EnDat 2.2 interface is a digital, bidirectional interface for measuring devices. It is able to output position
values of incremental and absolute measuring devices and read and update information stored in the
measuring device, as well as store new information. 4 signal cables are sufficient, due to the fact that the
data transfer is serial. The data is transferred synchronous with the clock signal specified by the downstream
electronics. The transmission type (position values, parameters, diagnostics ...) is selected via mode
commands, received by the measuring device from the downstream electronics. As a purely serial interface,
EnDat 2.2 is also suitable for safety applications.
Fig. 19: Signal cables and power supply for the EnDat 2.2 interface**
Incremental signals and ordering designation (HEIDENHAIN EnDat interfaces
)
**
Some encoders also provide incremental signals. These are usually used to increase the resolution of the
position value, or to serve a second subsequent electronics unit.
Current generations of encoders have a high internal resolution, and therefore no longer need to provide
incremental signals.