Data Exchange Between Controller And Pn/Can Link; Conversion Of Data Formats Between Profinet And Canopen - Siemens Simatic Operating Instructions Manual

Functions
4.1 CANopen
4.1.1.8

Data exchange between controller and PN/CAN LINK

Cyclic data exchange: Process data, control and status information
The process data configured in the HSP are transmitted cyclically as PROFINET data
between S7 controller and PN/CAN LINK.
The exchanged process data are stored in the PN/CAN LINK as entries in the object
dictionary (OD) (in index 2000h to 2FFFh). The values of the process data received by the
S7 controller are written to the OD by the PN/CAN LINK. The values of the process data to
be transmitted to the S7 controller are read from the object directory.
Control information and status information is exchanged cyclically between the PN/CAN
LINK and the S7 controller in "CANopen Manager" and in "CANopen Slave" mode.
The following controller information is cyclically transmitted by the S7 controller to the
PN/CAN LINK:
● Control bit for the state of the PN/CAN LINK
The user can influence the data transmission in the PN/CAN LINK from the S7 program
using a control bit.
● Reset bit
The user can reset the CANopen side in the PN/CAN LINK from the S7 program using a
reset bit.
Detailed information on the control and status information is available here:
CANopen Manager (Page 28)
CANopen Slave (Page 39)
Acyclic data exchange
The PN/CAN LINK provides 16 data records on the PROFINET side of the PN/CAN LINK
which the S7 user program can access with the help of the acyclic PROFINET IO services
RDREC (Read data record) and WRREC (Write data record).
Detailed information can be found under Acyclic data exchange between controller and
PN/CAN LINK (Page 31).
4.1.1.9

Conversion of data formats between PROFINET and CANopen

The process data are automatically converted from PROFINET to CANopen data format and
vice versa according to the configured data type.
The S7 controller interprets data in the "Big Endian" format. CANopen and the processors
used in the PN/CAN LINK use the "Little Endian" format. This means the sequence of bytes
is adjusted for all data types that exceed 1 byte.
Conversion takes places prior to writing the process data received by the S7 controller to the
OD or before the process data read from the OD are sent to the S7 controller.
The following table provides an overview of the data types supported by the PN/CAN LINK
and their conversion.
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SIMATIC PN/CAN LINK
Operating Instructions, 03/2018, A5E39895388-AB