Canopen Fieldbus Functionality; Supported Fieldbus Services - HMS CM CANopen User Manual

2. CANopen Fieldbus Functionality

The functionality of the CM CANopen Module for SIMATIC S7-1200 is defined by the CANopen CiA
301 rev. 4.2 specification and the CANopen CiA 302 Draft Standard Proposal rev. 4.1. The module can
be configured either as a manager or as a slave on the CANopen network.

2.1 Supported Fieldbus Services

Communication and parameters in the CANopen protocol are built around objects. There are different
services available to communicate with the objects and to perform other CANopen tasks like supervis-
ing the network. The following message types and objects are implemented in the CM CANopen Mod-
ule for SIMATIC S7-1200:
• NMT (Network Management)
or perform network and device monitoring, as well as handle errors. If the module is configured
as a slave, startup is performed by the manager.
• The CMT (Configuration Manager)
PDO parameters and mapping of information. If the module is configured as a slave, the con-
figuration is performed by the manager.
• PDOs (Process Data Objects) are used for I/O communication. There are 64 Receive PDOs and
64 Transmit PDOs implemented in the CM CANopen Module for SIMATIC S7-1200 that each
can transfer up to 8 bytes. Supported PDO message types are event driven (COS or timing), Cy-
clic Synchronous and Acyclic Synchronous
• SDOs (Service Data Objects) are asynchronous data transmission, and are used to access objects
without mapping them to an I/O (PDO) connection. Access is provided to all CANopen objects
in the module and in the network nodes (manager mode). SDO messages are used to configure
the modules and they can transfer more than 8 bytes, which is the upper limit for a PDO. (Ex-
pedited Upload/Download Protocol and Normal (Segmented) Upload/Download Protocol are
supported)
• A SYNC (Synchronization Object) is used for synchronizing PDO communication. A manager
can be either a producer or a consumer of the synchronization. A slave can only be a consumer.
• The Heartbeat Mechanism helps a device to monitor the status of another node. The module can
act either as heartbeat producer or consumer or both at the same time.
• The Node Guarding Protocol provides active surveillance of a slave by the manager. Slaves can
be configured to expect a node guarding request from the manager.
• An EMCY (Emergency Object) is used for error reporting when a fault has occurred in the mod-
ule and for reporting when all faults in a module have been cleared.
1. Only available when the module is configured as manager.
CM CANopen Module for SIMATIC S7-1200
Doc.Rev. 1.00
1
messages trigger the NMT state transitions for the slaves and/
1
configures the CANopen devices. This primarily involves
Chapter 2
Doc.Id. HMSI-216-117