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Chapter 12
nxp-servo
nxp-servo
is a CiA402 (also referred to as DS402) profile framework based on Igh CoE interface (An EtherCAT Master stack,
section for details). It abstracts the CiA 402 profile and provides an easily-usable API for the Application developer.
The nxp-servo project consists of a basic library
libnservo
and several auxiliary tools.
The application developed with
libnservo
is flexible enough to adapt to the changing of CoE network by modifying the
xml
config
file, which is loaded when the application starts. The
xml
config file describes the necessary information, including EtherCAT
network topology, slaves configurations, masters configurations and all axles definitions.
12.1 CoE network
A typical CoE network is shown in the figure below:
Figure 46. CoE network
There are three CoE servos on this network and we name them slave
x
as the position they are. Each CoE servo could have
more then one axle. The libnservo then initiates the CoE network and encapsulates the detail of network topology into axle nodes.
So the developer could focus on the each axle operation without taking care of the network topology.
12.2 Libnservo Architecture
nxp-servo
is running on top of
Igh
EtherCAT stack. And the
Igh
stack provides CoE communication mechanisms - Mailbox and
Process Data. Using these mechanisms, nxp-servo could access the CiA Object Dictionary located on CoE servo.
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