Sdo 1353 Response (Sdo-Miso); Types Of Sdo Objects - Curtis 1353 User Manual

Curtis 1353 CANopen Expansion Module Manual – June 2017

SDO 1353 Response (SDO-MISO)

An SDO request is always acknowledged with a response message from the 1353. The 1353 can issue
two kinds of response messages: a normal response or, in case of an error in the request SDO, an
Abort SDO Transfer message.
SDO-MOSI
The first data byte of the response contains an acknowledge code, which depends on the type of
transfer that was initially requested.
Data bytes 2, 3, and 4 hold the CAN Object index and sub-index of the request SDO.
If the SDO was a read command (a request for data from the 1353), data bytes 5 through 8 will be
filled with the requested values, with the LSB in data byte 5 and the next least significant in byte 6
and so forth. All unused bytes are set to 0.
If the SDO was a write command, data bytes 5 through 8 will return the actual value written in bytes
5 – 8. In this way, if the 1353 needs to limit or round-down the SDO write request, the master will
know—because the return value will be different than the sent value.
If the SDO-MOSI did not properly read or tried to access a parameter improperly, an Abort SDO
Transfer will be sent. Data bytes 5 through 8 will be filled with a 32-bit error code.

TYPES OF SDO OBJECTS

Three types of SDO objects are described in the following pages: Communications Profile Objects
(address range 0x1000), Device Parameter Objects (address range 0x3000), and Device Monitor Objects
(address range 0x3100).
pg. 24
(sent by the 1353 in response to the system master)
Byte 1 Byte 2 Byte 3
Control CAN Object
Index
0x06020000 = Object does not exist
0x06010002 = Attempt to write to a read only object.
Byte 4 Byte 5
Sub-index Data: either the requested Read values,
or the actual Write values, or an error code
Action Byte 1 Value
Read Response 0x42
Write Acknowledge 0x60
Abort SDO 0x80
Return to TOC
Byte 6 Byte 7 Byte 8
5 — SDO COMMUNICATIONS