NORD Drivesystems BU0570 - Manual (Page 6)

EtherCAT bus module for NORD frequency inverters SK 5xxE
6 Subject to technical amendments BU 0570 GB-0312
1 Introduction
1.1 General information
Modern field bus systems, microcontrollers and communication networks have had a great influence on
automation systems and have resulted in greater flexibility, availability and ultimately, also a reduction in
costs.
The widespread use of PC-based control only became possible with the availability of field bus systems.
With increasing control unit performance, the classic field bus ultimately became the limiting criterion for the
entire system. It was therefore an obvious step to adapt Ethernet technology, which provides high rates of
data transmission in IT applications, to the field of automation.
1.2 The bus system
In order to achieve real-time capability, EtherCAT uses a system which had already been used in a similar
form by Interbus. Ethernet packages are not first received, interpreted and then forwarded to participants by
each connected device, but rather each EtherCAT slave module extracts the data which is intended for it
whilst the telegram passes through the module. Output data is inserted into the telegram in the same way.
This results in delays of only nanoseconds.
EtherCAT® is a registered trademark and patented technology, licensed by Beckhoff Automation GmbH,
Germany.
Features of the SK TU3-ECT
 Static 8 byte process data for input and output
 Parameterisation via CoE (CAN over EtherCAT)
 Error messages (emergency messages) compliant with CANopen DS301
 EtherCAT addressing via DIP switches
 Distributed Clocks are not supported
Performance
 Via the SK TU3-ECT, up to 1000 frequency inverters can each update their process data (8 byte
input and output data) in a cycle of one millisecond.
 An update interval for process data between the SK TU3 ECT and the SK 500E requires
approximately1.5 ms
 Reading access to a parameter on the SK 500E requires about 25ms
 Writing access and storage of a parameter in the EEPROM requires about 70 ms.