Altivar Process ATV900 - Service Data Communication (SDO)

Basics
20
NHA80945 04/2017
Service Data Communication
Description
Service Data Objects (SDO) can be used to access the entries of an object dictionary using index and
subindex. The values of the objects can be read and, if permissible, also written.
Every network device has at least one SDO server to be able to respond to read and write requests from
a different device.
The TSDO of a SDO client is used to send the request for data exchange; the RSDO is used to receive.
The data frame of a SDO consists of 8 bytes.
SDOs have a higher COB ID than PDOS, therefore they are transmitted over the can bus at a low priority.
Example of Read Request
This example explains how to read the acceleration (ACC) parameter on an Altivar located at CANopen
address 4 (COB ID = 580 hex + Node ID or 600 hex + Node ID). The index / subindex value of this
parameter is 203C/02 hex. Values are given in hexadecimal.
Read request: Master → Drive
Read response: Master ← Drive
The value of parameter read is equal to 1000 (03E8 hex), equivalent to an acceleration (ACC) of 100 s, as
the unit of this parameter is 0.1 s.
Example of Write Request
This example explains how to write the value 100 s to the acceleration (ACC) parameter on an Altivar
located at CANopen address 4 (COB ID = 580 hex + NodeID or 600 hex + Node ID). The index / subindex
value of this parameter is 203C/02 hex. Values are give in hexadecimal.
The request code is 2B hex for an item of 2 bytes data length.
Write request: Master → Drive
The request data field indicates the value 03E8 hex as value written is 1000, equivalent to an acceleration
(ACC) of 100 s, as the unit of this parameter is 0.1 s.
Write response: Master ← Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
COB ID Request
code
Object index Subindex Request data
604 40 3C 20 02 00 00 00 00
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
COB ID Request
code
Object index Subindex Request data
584 4B 3C 20 02 E8 03 00 00
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
COB ID Request
code
Object index Subindex Request data
604 2B 3C 20 02 E8 03 00 00
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
COB ID Request
code
Object index Subindex Request data
584 60 3C 20 02 00 00 00 00