86/176 CANopen
Bosch Rexroth AG, MIT: ID 40, 3 842 530 344/2014-05
All object index and subindexes are written in this manual in hexadecimal format
without prefix or suffix.
The following example shows the object name of the actual link state 2600/01
The index is 2600 [hex] and the subindex is 01 [hex].
The EDS file (see Chapter 9.18 “Electronic data sheet [EDS]”) defines the object
directory for the ID 40 system. The application obtains information from the EDS file
that provides objects in the ID 40 system.
9.3 Command-oriented data exchange
Command-oriented data exchange occurs via SDO. An SDO is a confirmed data
transmission, i.e., the execution of an SDO is reported. If, e.g., an SDO reports “OK”
after entering data in the MDT, it is ensured that the data was entered in the MDT
memory.
The SDO service allows unrestricted access to the ID 40 system and supports the
following functions:
• Writing data, e.g., MDT data in CONNECTED state or the link state switch request
• Reading data, e.g., MDT data in CONNECTED state or reading the actual link state
• Configuring prefetch and pretransmit (see Chapter 9.5 “MDT data transmission
with transfer buffers”)
• Configuring event-oriented data exchange
• Configuring and running diagnostics for the SLK on CAN, e.g., communication
parameters
To use the SDO service, a PLC with a CANopen master module provides SDO
function blocks. This allows the data to be read and written by command. The
application and parameters of such function blocks depend on the PLC or module
and are documented in the relevant manuals.
One parameter needed for SDO communication is the object index. Other
parameters are data source or data sink. The SDO takes the bytes transmitted to
the SLK from the data source, e.g., a data block. Data read from the SLK via SDO is
entered by the function block in the data sink, usually also a data block in the PLC.
9.4 Event-oriented data exchange
During event-oriented data exchange, the ID 40 system sends objects whose value
has currently changed.
Example: MDT data read with the prefetch function. This allows the application to be
automatically notified of an MDT entering the SLK field.
PDO services are available for event-oriented data exchange (see Chapter 9.9 “PDO
communication”). Contrary to SDOs, PDOs are messages that are not confirmed by
the recipient.
PROOF COPY 1 | 20.05.2014 | FOR INTERNAL USE ONLY
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