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E.1.4.2 sdo (service data object) – Delta Electronics AC Motor Drive VFD-E User Manual

Page 355

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Appendix E CANopen Function |

E-6

Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11

Initializing Pre-Operational Operational Stopped

PDO

SDO

SYNC

Time Stamp

EMERG

Boot-up

NMT

NMT Protocol is shown as follows:

NMT Master

Request

request

CS

Node-ID

COB-ID=0

Start Remote Node

NMT Slave(s)

Indication

byte 0

byte 1

Indication

Indication

Indication(s)

Cs

Value Definition

1 Start
2 Stop

128 Enter

Pre-Operational

129 Reset

Node

130 Reset

Communication

E.1.4.2 SDO (Service Data Object)

SDO is used to access the Object Dictionary in every CANopen node by Client/Server model.

One SDO has two COB-ID (request SDO and response SDO) to upload or download data

between two nodes. No data limit for SDOs to transfer data. But it needs to transfer by

segment when data exceeds 4 bytes with an end signal in the last segment.

The Object Dictionary (OD) is a group of objects in CANopen node. Every node has an OD

in the system, and OD contains all parameters describing the device and its network

behavior. The access path of OD is the index and sub-index, each object has a unique index

in OD, and has sub-index if necessary.

The request and response frame structure of SDO communication is shown as follows: