LINEPULS & LINECOD catalogue 2016 in English

LINECOD
Output circuits and fieldbus interfaces
First developed in the automotive industrial sector, CANbus (Controller Area Network)
serial bus system has thereafter established itself in a variety of industrial applications,
in particular where noisy electrical environment conditions could lead to unsafe communication.
International Organization for Standardization (ISO) has established the CAN standard in
ISO 11898, developing the protocol over the first two layers of the ISO/OSI (Open Systems
Interconnection) reference model; while all the other protocol layers are the network designer’s
choice. Unlike other protocols that define all ISO/OSI layers, developers intentionally
limited the CAN specifications so manufacturers are free to choose a specific implementation
of the higher protocol layers; for this reason other CAN-based protocols have been
developed at higher layers as CANopen and DeviceNet or other proprietary protocols.
CANbus standard and CANopen communication protocol are administered by CAN in Automation
(www.can-cia.org). CANopen is widely used in Europe.
CANopen is a CAN-based communication protocol which implements the higher layers of
the ISO/OSI (Open Systems Interconnection) reference model. Its technology development
and standardization are entrusted to CiA (CAN in Automation).
CANopen is a Single Master - Multi Slave communication protocol. Master device is able
to detect all the Slaves connected to the network thanks to the EDS (Electronic Datasheet)
configuration file which is provided by the device manufacturer. The EDS file contains the
complete list of all the working parameters of the Slave device and information for configuring
the communication between the Master and the Slave.
In the CANopen network, the Master device must be addressed to 0, while the Slave nodes
have address between 1 and 127. Maximum transmission rate is up to 1Mbit/s.
The following table shows the maximum transmission rates in relation to permissible line length.
Baud rate
[Kbit/s]
Max. cable
length
10 20 62.25 125 250 500 800 1000
5000 m
16400 ft
2500 m
8200 ft
1000 m
3300 ft
500 m
1650 ft
250 m
820 ft
100 m
330 ft
50 m
165 ft
30 m
100 ft
Lika encoders with CANopen interface comply with the “Device Profile for encoders” Class 2
established in the “CIA Draft Standard 301” and the “CIA Draft Standard 406” publications.
Lika devices with CANopen support the CANopen network management (NMT) slave state
machine (Initialization state, Pre-operational state, Operational state, Stopped state) and
use COBs (Communication Objects), in particular: NMT (Network Management) messages to
issue state machine change commands (i.e. to start and stop the devices) and detect remote
device boot-ups and error conditions; PDO (Process Data Object) messages to process real
time data (transmission of process data in real time); and SDO (Service Data Object) messages
to set and read values from the “Object dictionary” of the remote device. Furthermore
they implement some standard objects such as the synchronization object (SYNC) and the
Nodeguarding. Among the parameters available: position readout, counting direction, scaling
function, preset and offset values, two min. and max. software limit switches, errors
register and diagnostic information. Encoders can be fitted with diagnostic LEDs and bus
termination resistance.
CANopen at a glance
Number of
stations
Setting the
nodes
Setting the
baud rate
Transmission
rate
Cable length
Cable
Up to 127
Dip switches
or software
Dip switches
or software
Up to
1Mbit/s
Up to 5000 m/
16400 ft
Standard CANopen/
M12 connectors
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