Siko MSA501, User Manual

Page: 18 / 51

Communication via
CAN bus (CANopen)
MSA501
Date: 12.10.2018 Art. No. 88734 Mod. status 330/18 Page 18 of 51
5.4.1.2 Normal Request/Response
If more than 4 bytes of service data are to be transferred, the data is exchanged between two
subscribers via the normal Request/Response. This procedure is also initiated by an
initialization message, and the actual user data will be transferred in the subsequent segment
messages.
For the MSA501 this is only the case with reading of the object 1008h: Manufacturer Device
Name .
The initialization message has the following structure:
COB-ID User data in binary code
Byte 0
read /
write
Byte 1
LSB Byte 2
MSB Byte 3 Byte 4
LSB Byte 5 Byte 6 Byte 7
MSB
SDO rx/tx
+ Node-ID Command
byte index Sub-index User data (number of user data)
The segment message has the following structure:
COB-ID User data in binary code
Byte 0
read /
write
Byte 1
LSB Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
MSB
SDO rx/tx
+ Node-ID Command
byte User data
Initialization and segment message: Command byte, byte 0:
The command byte determines the type of access and the number of valid data bytes. The
following command bytes are valid for the MSA501:
Command byte Type Function
Read Request 40h SDO (rx), Normal Initiate
Upload Request Request parameter from slave
(number of bytes to be
transferred).
Read Request 60h SDO (rx), Normal Segment
Upload Request Request parameter from slave (user
data)
Read Response 41h SDO (tx), Normal Initiate
Upload Response Report parameter to master
(number of bytes to be
transferred).
Read Response 03h SDO (tx), Normal Segment
Upload Response Report parameter to master (user
data)
Error Response 80h SDO (tx), Abort Domain
Transfer Slave reports error code to master
Table 14: Command coding