SFA-5000 • SFA-10000 CANopen®
6.5 Boot-up objects
Boot-up message structure:
COB-ID (hex)
1 CAN Data Byte
700+Node ID
00
6.6 PDO objects
PDO (tx) messages are always made up of four CAN Data Bytes and are used by
the encoder to transmit the position value and/or the velocity value.
PDO structure:
IDENTIFIER
4 CAN Data Bytes
COB-ID (hex)
Byte 0
Byte 1
Byte 2
Byte 3
F.C.
Node-ID
Low
…
…
High
position value (with PDO1, PDO2, PDO3)
velocity value (with PDO4)
Four types of PDO messages are defined, they are:
PDO1 Cyclic mode
: cyclic transmission of position value
The encoder uses the PDO1 message to transmit the position value
cyclically
,
i.e. periodically and independently from the Master.
The interval between two issues is set in the
object.
To activate (or deactivate) the cyclic mode it is necessary to set to 0 (or 1) the
most significant bit of COB-ID used by PDO1 (
, sub 1 object).
PDO2 and PDO3 SYNC mode
: synchronous transmission of position value
The transmission of the position value is managed by the Master
by sending a
SYNC message
.
SYNC message is a high-priority COB transmitted by the Master to request the
position value of the encoder through a PDO.
If several nodes (encoders) are connected to the network, the Master receives
the position values from the Slaves according to the order of the Node
addresses.
The encoder can be programmed to send a reply after a set number of SYNC
messages by setting a counter.
The PDO message will be transmitted after having received the set number of
SYNC messages.
For PDO2 the value of the counter must be set in the
, sub 2 object.
1802 TPDO communication parameter 3
, sub 2 object.
MAN SFA_5000_10000_CB E 1.0.odt
6 - CANopen® interface
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