User Manual of iSV2-CAN Servo
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58
Master to Slave(Write)
COB-ID(hex)
Byte 0
Byte 1:2
Byte 3
Byte 4:7
0x600+Node-ID
SDO send Command
Object Dictionary
Index
Data
Slave to Master(Feedback)
COB-ID(hex)
Byte 0
Byte 1:2
Byte 3
Byte 4:7
0x580+Node-ID
SDO receive Command
Object Dictionary
Index
Data
Example of SDO:
⚫
The master uses the SDO to write data to objects in the nodes
COB-ID Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
Description
Master to Slave(Write)
Setup into Node 2
1081h-03=20F0(hex)
602
2B
01
18
03
F0
20
00
00
Slave to Master(Feedback)
582
60
01
18
03
00
00
00
00
⚫
The master uses the SDO to read data from objects in the nodes
COB-ID Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
Description
Master to Slave(Write)
Read from Node 2
1081h-03=20F0(hex)
602
40
01
18
03
00
00
00
00
Slave to Master(Feedback)
582
4B
01
18
03
F0
20
00
00
5.5 PDO
PDOs are messages send without confirmation used for real time information transfer. PDOs are mapped to a
single CAN frame and can contain multiple object dictionary entries with a maximum of 8 bytes of data. Each
PDO has an identifier and is transmitted by only one node in the network, however it could be received by
more than one node. PDOs must be configured previous to using them.
There are two types of PDO messages: Transmit PDO (TPDO) and Receive PDO (RPDO).
The trigger event of the PDO message could be configured using the communication parameter object and the
object dictionary entries transmitted could be also defined using the PDO mapping list.
Therefore, each PDO is defined by means of:
⚫
A PDO communication parameter
⚫
A PDO mapping object
iSV2-CAN series include 4 RPDO and 4 TPDO.
Transmit PDO (TPDO)
TPDOs are configured to send data from node to master after the occurrence of a trigger event or after a
remote request by means of a RTR.
TPDOs have three transmission types:
⚫
Internal event or timer:
Message transmission is triggered when the value mapped into the PDO
has changed or when the specified time (event-timer) has elapsed. PDO transmission is controlled by
producer.
⚫
Remotely request:
Message transmission is initiated on receipt of a RTR message. PDO
transmission is driven by the PDO consumer.