Pixsys MCM260X User Manual

48 - MCM260X - Manuale d’uso
11.1.3 CANopen identifier distribution
The COB-ID can be determined in 3 ways:
• Pre-defined Connection Set: it is the way shown in the previous section. Allocation is by default
and other configurations are not necessary.
• PDO identifiers (COB-ID): they can be modified after powering on the instrument, when it is in the
Pre-Operational status (see next section). In this status, new values can be written in the Object
Dictionary only with the SDO.
• Using DBT (Distributor, a service CAL): the nodes are initially identified by their node-ID.
The Node-ID of the slave node can be configured by internal dip-switches or by LMT (Layer
Management, a CAL service). When the network initializes and boots, the master communicates
with each connected slave with a ‘telegram’ (an NMT service). Once this connection has been
established, DBT provides allocation of CAN identifiers for communication of SDOs and PDOs to
the nodes.
11.1.4 CANopen boot-up procedure
Network initialization supports two boot-up processes: Minimum boot-up and Extended boot-up. The
first is a pre-requisite for a CANopen device, the second is optional but is necessary if the COB-ID must
be allocated by the DBT services. The transition diagram below shows a minimum boot-up procedure
for a CANopen node.
Initialization
Power-On
Reset Node
Reset
Communication
Initialization finished
Enter Pre-Operational
Enter Operational
Start
Remote
Node
Stop Remote Node
Start Remote Node
Error
Pre-Operational
Operational
Stopped
Stop Remote Node
The NMT services allow the status to be changed in each condition. NMT messages are formatted by
a CAN-header (COB-ID = 0) and 2 data byte. A byte contains the requested service (NMT command
specifier) and the other contains the Node-ID (0 for broadcast mode). A CANopen network can only
have an NMT master, which brings NMT messages and controls the initialization processes.
The CANopen devices supporting only the minimum boot-up enter the Pre-Operational
status automatically, immediately after ending the initialization. In this status, COB-ID allocation and
parameter setting are possible from SDOs only.
The MCM260X module moves automatically to the Pre-Operational status after ending the boot-up.
11.1.5 Communication profile: initialization
In most cases, a default configuration is assigned to the Object dictionary, if there are no other user
configurations saved. The default configuration does not provide for any pre-set PDO. To use the PDO,
both Tx and Rx, in the module initialization phase it is necessary for the CANopen master to execute
the correct mapping.

Pixsys MCM260X Specifications

General

Brand	Pixsys
Model	MCM260X
Category	Network Hardware
Language	English