LINEPULS & LINECOD catalogue 2016 in English

LINECOD
Output circuits and fieldbus interfaces
EtherCAT (Ethernet for Control Automation Technology) is an open Ethernet-based
fieldbus system which applies Ethernet features to fieldbus technology.
Its development and administrative management are entrusted to the EtherCAT Technology
Group (ETG) (www.ethercat.org). EtherCAT bus is simply a single large Ethernet “device”
which receives and sends Ethernet telegrams (standard Ethernet dataframes in accordance
with IEEE 802.3).
However, the “device” does not contain an Ethernet controller, but one Master and some
Slaves. Moreover any control with a commercially available Ethernet controller should be
able to be used as an EtherCAT Master: standard structural components such as Ethernet
switches in fact should be usable for EtherCAT. Telegrams are processed directly “on the fly”.
While the telegrams (delayed by only a few bits) are already passed on, the Slave recognizes
relevant commands and executes them accordingly. Processing is done within the hardware
and is therefore independent of the response times of any microprocessors that may be
connected. Flexible topology variants arbitrarily extendable namely Line, Star, Tree, Daisy
Chain + Drop Lines are possible, even in the same network. Slave configuration can be done
both via XML configuration file (EtherCAT Slave Information ESI) provided by the device
manufacturer and by loading data directly from EEPROM (Slave Information Interface SII).
The number of devices which can be installed in the EtherCAT network is virtually unlimited,
while up to 65,535 nodes can be connected for each segment.
The transmission rate is 100 Mbit/s with full-duplex communication (Fast Ethernet).
Lika encoders with EtherCAT interface are Slave devices and support the CANopen Over
EtherCAT (CoE) protocol for data transfer; in particular they comply with the “Device Profile
for encoders” Class 2 established in the “CIA Draft Standard 301” and the “CIA Draft Standard
406” publications for CANopen; furthermore they comply with the EtherCAT standard
established in ETG.1000 protocol conformance. As CANopen communication protocol, also
EtherCAT uses PDOs and SDOs. PDO (Process Data Object) messages are used to process real
time data (transmission of process data in real time, bus cycle time of 62 μs only, the faster
in the market); while SDO (Service Data Object) messages are used to set and read values
from the “Object dictionary” of the remote device. The following transmission modes are
available: FreeRun: asynchronous mode, encoder position is sampled directly from EtherCAT
frame sent by the Master; position update is performed by an internal timer of the controller
every 100 microseconds; Synchronous with SM3: data is sampled and then copied into Sync
Manager buffer as soon as the previous data are read by the Master (SM event); in this way
new sampled data is synchronous with Master readings; Synchronous with DC: data is sampled
and then copied into Sync Manager buffer simultaneously at SYNC0 event generated
by the ESC capture/compare unit. Furthermore, Lika devices support the ESM (EtherCAT State
Machine) with Init state, Pre-operational state, Safe-Operational state and Operational
state; they also implement the FOE (File Access over EtherCAT) protocol for firmware update.
Among the parameters available: position readout, counting direction, scaling function, preset
and offset values, errors register and diagnostic information.
They are fitted with diagnostic LEDs and do not need any bus termination resistance.
EtherCAT at a glance
Number of
stations
Setting the
nodes
Setting the
baud rate
Transmission
rate
Cable
length
Cable
Virtually
unlimited
Software,
automatic
-
100 Mbit/s
full duplex
Up to 100 m
/ 330 ft
Standard
EtherCAT /
M12 connectors
48