Communication extension card
-29-
e code
Byte0
Byte1 Byte2
Byte3
Byte4 Byte5 Byte6 Byte7
0x583
0x43
0x01
0x18
0x03
0xe8 0x03 0x00 0x00
Read/write error example: The master station transmits the following read operation command to read an
object (whose index is 0x6000 and subindex is 0x00) that cannot be found.
COB-ID
Request
code
Object index Subindex
Requested data
Byte0
Byte1 Byte2
Byte3
Byte4 Byte5 Byte6 Byte7
0x603
0x40
0x00
0x60
0x00
0x00 0x00 0x00 0x00
The object cannot be found, and therefore the slave station transmits the following read/write error
command response.
COB-ID
Respons
e code
Object index
Subinde
x
Response data
Byte0
Byte1 Byte2 Byte3 Byte4 Byte5 Byte6 Byte7
0x583
0x80
0x00
0x60
0x00
0x00
0x00
0x02
0x06
The error code in the response is 0x06020000, indicating that "
Object cannot be found in the object
dictionary
".
3.5
Process data object (PDO)
The communication card provides four PDO Tx commands (whose indexes are 0x1800 to 0x1803) and four
PDO Rx commands (whose indexes are 0x1400 to 0x1403). PDO Rx is a PDO command transmitted by the
master station to a slave station, that is, it is a master station command. PDO Tx is a PDO command
transmitted by a slave station to the master station.
The CW, SW, setting, and return value of each PDO of the communication card are all defined with a
"manufacturer-defined object dictionary". In this way, the process data of a VFD can be monitored not only
through PDOs but also through SDOs. For more information, see the next chapter. Each PDO command is
labeled with "manufacturer-defined object dictionary" in the format of 0xXXXX.HH, where XXXX indicates
an index, HH indicates a subindex, and both of them are hexadecimal.
3.5.1
Triggering mode of PDO Tx
Each PDO Tx is defined with a transmission type, disabled time, and event timer. The corresponding subindex
of the transmission type is 0x02, that of the disabled time is 0x03, and that of the event timer is 0x05.
Therefore, the object dictionary index corresponding to PDO2 Tx is 0x1801, and the subindex is 0x02. The
same principle applies to other PDO Tx commands. For more information, see Appendix A.
Synchronous triggering: When the transmission type is set to 1 to 240, PDO Tx is synchronous transmission.
For example, if you set the transmission type of PDO2 Tx to
n
(1≤
n
≤240), a slave station transmits one PDO2
Tx command every time after it receives
n
synchronous packet objects. The same principle applies to other
PDO Tx commands.