6 Operation

IL•1F CANopen DS301

6.2.2Reading a parameter

Task The parameter Status.n_act, 31:9 (actual speed) is to be read.

Index and subindex must be converted to hexadecimal notation and the constant 3000h added to the index for the SDO access:

Index:31 = 1Fh + 3000h = 301Fh

Subindex 9 = 09h

The value "40h" must be entered as the CCD. This value identifies a "Read Request".

Transmit data

Object

COB ID

CCD

Idx

Sdx

Data

Description

Tx 301Fh:09h Sta-

600h+ID

40h

1Fh 30h

09h

XX XX XX XX Reads the actual speed. The data

tus.n_actT

 

 

 

 

 

has no significance.

 

 

 

 

 

 

 

The 4 data bytes have no significance for a read request.

Receive data

Object

COB ID

CCD

Idx

Sdx

Data

Description

Rx 301Dh:09h Status.n_act

580h+ID

43h

1Fh 30h

09h

E8 03 00 00

The data 000003E8 corresponds

 

 

 

 

 

 

to 1000 min-1.

The product transmits the data as 32 bit values back to the master (CCD is "43h"). It also sends back data as a 32 bit value which are described as INT16 or UINT16 data types in the product manual. When an INT16 or a UINT16 value is read, it is therefore possible to evaluate all 4 data bytes. However, for 16 bit data it is also correct to evaluate only the first two data bytes and to ignore the last two data bytes.

6.2.3Synchronous errors

Receive data with error frame "Error If an SDO write or read command fails, the product responds with an er- Response" ror frame "Error Response". This may happen if, for example, you try to

read or write a non-existent object. The transmitted error number pro- vides information on the exact cause.

Object

COB ID

CCD

Index

Sub

Data

Description

Rx 3028h:20h

580h+ID

80h

28h 30h

20h

00 00 02 06

Error value 06020000h means

 

 

 

 

 

 

"object does not exist in object dic-

 

 

 

 

 

 

tionary"

 

 

 

 

 

 

 

The example shows the response to a write or read request for a non- existent object 40:32.

The error number of a synchronous error message is stored as a UINT16 value and the corresponding CCD (Error Response) is as- signed the value 80h. Refer to 7.3.2 "Error code table" for a table with the error numbers.

0198441113586, V2.01, 11.2008

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Fieldbus interface

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Schneider Electric DS301 manual Reading a parameter, Synchronous errors, Index Sub Data Description