Lenze CANopen control technology - Manual (Page 25)

DMS 4.2 EN 07/2011 TD17
L
25
Control technology | CANopen communication manual
Planning the CANopen network
6 Planning the CANopen network
Before establishing a CANopen network, create a plan of your Logic bus and/or your
Motion buses.
For this purpose, create an overview screen of the planned CANopen network with all field
devices to be implemented. Start with the Industrial PC and arrange the other field devices
below it. (see Example of an overview screen ( 28) ).
Provide the following data for each device:
Type Type designation of the field device
Used CAN interface of the device "Logic before Motion":
• Always connect an existing Logic bus to the 1st CAN interface (CAN1).
• Motion buses, however, can be connected to every CAN interface.
CANopen (Logic) / CANopen (Motion) ( 15)
Unambiguous CAN node address • If system bus (CAN) devices are used, max. 63 nodes/node addresses are
possible.
• With CANopen-compliant devices, up to 127 nodes/node addresses are
possible.
Note: Do not use the node address 1, in order to avoid unintentional mistakes
and conflicts with a device containing the factory adjustment.
Baud rate • The baud rate applies to all nodes of the CANopen network.
• 50, 125, 250 and 500 kbit/s are supported by all device types of the system.
• Observe the dependency between bus cable length and baud rate. Bus
cable length ( 22)
Master role of the device
(NMT master/sync master)
• An NMT master sets itself and then the NMT slaves to the "Operational" state.
In this state, process data can be communicated. Generally, there can be an
optional number of NMT masters on one CANopen bus.
• A sync master cyclically sends a sync telegram providing for an exactly
simultaneous processing of process data and/or a simultaneous task start in
all sync receivers.
• Via CAN synchronisation you can influence the exact time of the following
events in the field device:
–Acceptance and transmission of sync-controlled PDOs
–Starting time of the task of the application (only possible for Servo Drives
9400)
• You only need to use CAN synchronisation on the Logic bus if an exact
simultaneity in the range of milliseconds is of importance. A mere operating
periphery (operator button, control lamps, etc.) does not require CAN
synchronisation.
CAN objects and COB-IDs • Plan your COB-IDs according to the CANopen DS301 communication profile.
This convention is optimised for the communication with a central master
device. COB-IDs acc. to DS301 ( 26)
• Up to 4 PDOs per device can be identified with this scheme. If you require
more, e.g. for a modular I/O system with more than 8 modules, you can add
them later.
• You can easily assign the node during the bus diagnostics by means of the
COB-IDs.
• COB-ID = basic identifier + node address