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5.1.1.3
Process data objects (PDO)
Process data objects
Process data are transmitted on the CANopen side by means of PDOs.
The PN/CAN LINK supports 512 PDOs for transmitting/receiving.
One entry exists in the OD for the "Communication parameters" and one entry for the
"Mapping parameters" for each receive PDO (RX-PDO) and each transmit PDO (TX-PDO).
In the configuration you specify:
• The COB ID of the CAN message
• The format of the COB-ID (11b or 29b)
• The transmission mode (synchronous, event-controlled with timer, RTR)
• Whether or not the PDO is active
• The OD entries onto which the transmitted or received PDOs are mapped
Transmission types
The PN/CAN LINK supports the following PDO transmission types:
Transmission method
Acyclic synchronous
Cyclic synchronous
RTR only
Manufacturer-specific event control
Application-specific event control
SIMATIC PN/CAN LINK
Operating Instructions, 03/2022, A5E39895388-AC
Description
PDO is transmitted during the next "SYNC" after a value
change
Depending on the configuration, PDO is transmitted for
each first to 240th "SYNC" regardless of value changes
On request only (RTR message synchronous /
asynchronous)
PDO is only transmitted after a RTR message with the
COB ID of the PDO was received. The PN/CAN LINK only
supports transmission method "RTR only" for transmit
PDOs and not for receive PDOs.
These transmission types are event-controlled
(asynchronous).
PDO is transmitted following an event, that is a value
change, as well as after expiration of a configured
timeout, regardless of "SYNC".
Event-controlled transmit-PDOs with transmission type
254 (manufacturer-specific) and transmission type 255
(application-profile specific) are also transmitted during
the transition to the NMT state "Operational".
Functions
5.1 CANopen
35
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