IFM ecomat 100 R 360 Series, System Manual

Page: 36 / 166

page 36
6.5. General remarks on the CAN utilization
If in connection with the plc ecomat R 360 CAN or CANopen is
used, some points must be taken into account. They concern
the physical structure of the CAN network and the correct
software handling.
Physical network structure The following applies to the CAN network structure:
•
Ensure that the selected data transmission rate is not higher
than needed. A low transmission rate increases the
operational reliability.
•
The cable length must match the data transmission rate. For
R 360 it is typically 400 m at 125 kBaud.
•
Lay the bus cable in a line and avoid spurs. Ensure clean
and firm terminal locations to avoid unnecessary contact
resistance. If necessary, lay the cables as a twisted pair with
or without a screen.
•
Fit both ends of the bus cable with a terminating resistor of
120
Ω
.
•
The higher the number of the participants in the network, the
more carefully the network must be laid out (cable version,
cable length, etc.).
Software for CAN and CANopen In principle, R 360 can directly take part in the CAN
communication (layer 2) by using the functions
CAN_TRANSMIT and CAN_RECEIVE. In the CANopen mode
the programmer is supplied with the defined services.
The following points must be considered:
•
In the direct CAN mode in layer 2 the programmer is
responsible for all services. The plc is in this state after a
program download or a reset command by the programming
system.
•
For the direct CAN mode the cyclical integration of the
function block CAN_ERRORHANDLER is recommended.
Otherwise, the application program must perform a
CAN_RESTART in the case of BUS_OFF.
•
After a program download or a reset command by the
programming system the plc is not yet a CANopen device.
To change to the CANopen mode the flag CAN_OPEN must
be set at the start of the program. The R 360 then operates
as a CANopen slave.
•
If a R 360 slave is stopped via the programming software, a
following node start command of the CANopen master is
ignored. However, a stop command of the master
(NMM_SET_PREPARED) is always executed.