4 description of the objects, Description of the objects, Canopen communication – Lenze 931K User Manual
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CANopen communication
Process data transfer (PDO transfer)
Description of the objects
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35
KHB 13.0002−EN 4.1
5.3.4
Description of the objects
Identifier of the PDO (COB_ID_used_by_PDO)
The identifier on which the respective PDO is to be sent or received must be entered in the
COB_ID−used_by_PDO object. If bit 31 is set, the respective PDO is deactivated. This is the
default setting for all PDOs. In addition, bit 30 (no RTR allowed) must be set for every access.
The COB ID can only be changed if the PDO is deactivated, i.e. if bit 31 is set. For changing
the COB ID, you therefore have to keep to the following sequence:
ƒ
Read out the COB ID
ƒ
Write the read−out COB ID + C0000000
h
ƒ
Write the new COB ID + C0000000
h
ƒ
Write the new COB ID, the PDO is active again.
Transmission mode (transmission_type and inhibit_time)
For each PDO, the event leading to a message being sent (transmit PDO) or evaluated
(receive PDO) can be defined:
Value
Meaning
Permitted for
00
h
− F0
h
Sync telegram
TPDO
RPDO
The numerical value specifies how many sync telegrams are ignored between two
transmissions before the PDO is
− sent (TPDO) or
− evaluated (RPDO).
FE
h
Cyclic
TPDO
(RPDO)
The TPDO is cyclically updated and sent by the drive controller. The time interval is
specified with the inhibit_time object.
RPDOs, however, are evaluated immediately after the receipt.
FF
h
Change
TPDO
The TPDO is sent if at least one bit of the PDO data has changed.
The inhibit_time can be used to additionally specify the minimum time interval (in
100
ms steps) between the transmission of two PDOs.
The use of all other values is not permitted.
Number of objects to be transferred (number_of_mapped_objects)
This object specifies how many objects are to be mapped into the corresponding PDO. The
following restrictions have to be taken into account:
ƒ
It is not possible to map more than 4 objects per PDO
ƒ
A PDO can have a maximum of 64 bits (8 bytes).