CANDPSX user manual rev 2 Page 18 of 42
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Format and elements of the result control structure mapped in the Profibus dual port (parameter
20A4h):
Elements of the SDO result control structure
request result according to CANopen:
0 = request fulfilled
1 = the object does not exist
2 = the subindex does not exist
3 = read-only object
4 = the object cannot be written while in this state
5 = lower bound
6 = higher bound
7 = internal control failed
8 = illegal value
9 = illegal access to the object
10 = generic error
11 = unable to save
12 = invalid signature
13 = toggle error
14 = time out
15 = invalid command
16 = write-only object
17 = mismatching length
18 = length too large
19 = length too small
20 = the object cannot be mapped
21 = object too large for PDO
100 = time out
101 = system error
102 = system error
103 = invalid command
104 = inconsistent data
105 = invalid protocol length
106 = toggle error
size of received data in the buffer 20A6h
Note: if the memory swap function is active, the elements of the control structure will be swapped.
The field “len” will be in “byte 1” and “ack” will be in “byte 3”. .Profibus-DP master’s algorithm to
exchange objects with slave nodes:
If a write-object request is to be executed, it writes to the parameter 20A5h the data of
the object to be sent to the slave node
It writes to the parameter 20A3h the index and subindex of the object to be exchanged,
the ID of the node with which the object is to be exchanged and, if a write-object request is
to be sent, the length of the data stored in the parameter 20A5h
It reads the status of the acknowledgement byte from the parameter 20A4h
It writes the type of request to the parameter 20A3h
It waits for the acknowledgement byte in the parameter 20A4h to vary
It checks the result of the request in the parameter 20A4h
If a write-object request was sent, it retrieves the data from the parameter 20A6h
It resets the request in the parameter 20A3h
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