Flintec EM100-C - Canopen Frames; SDO CAN Frame

EM100-C User Manual
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Page 76 of 81
6.3. CANopen Frames
A CANopen data telegram or frame is constructed as below. The EM100 uses expedited transfer
only i.e. each communication is contained within one frame (not sent over several).
For CANopen purposes an EM100 module is the ‘Server’ and CAN Master is the ‘Client’.
6.3.1. SDO CAN Frame
This has 4 components:
The COB-ID uniquely identifies what communication type it is and its destination (request) OR origin
node (response).
Specifier – indicates to the EM100 a command or response.
Parameter – which object (index) is to be read or written.
Data – the data read or written to the object.
COB-ID
Hex. Value
Transmission
600Hex.
Master  EM100.
580Hex.
EM100  Master.
The node ID is added to this value so to communicate with node 4.
Master node  EM100 node uses 604Hex.
EM100 node  Master node uses 584Hex.
The command specifier is broken down as follows:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SP
Reserved
N
E
S
SP:
1 = Write object value to EM100 (SDO Download request)
2 = Read object value from EM100 (SDO Upload request and response)
3 = Confirmation of write (ACK)
4 = Abort SDO transfer.
When data is being written to or returned from the node the following applies:
for upload requests they are 0.
E: 1 = expedited i.e. data is in bytes 4-7 (always true).
S: =1 if data size is defined.
N: If S = 1, then the number of data bytes that do not contain data (of bytes 4-7).