Modbus request example

At a Glance

From a Man Machine Interface (example : XBT), it is possible to access the SDOs using the Modbus FC43 request

SDO read example

Node reading 1F, object 1005, subindex 00, length 8 bytes

FC	MEI	Prot	Nid	Index	Sub	Offset	Length
2B	0D	00	1F	10 05	00	00 00	00 08

Response OK: reception of 4 bytes

FC	MEI	Prot	Nid	Index	Sub	Offset	Length	Object value
2B	0D	00	1F	10 05	00	00 00	00 04	80 00 00 00

Failure: SDO cancellation code

FC	MEC	Ext length	MEI	Excpt code	SDO abort code
AB	FF	00 06	0D	EC	06 02 00 00

Write SDO example

Node reading 1F, object 203C, subindex 02, length 2 bytes 03 E8

FC	MEI	Prot	Nid	Index	Sub	Offset	Length	Data
2B	0D	01	1F	20 C3	02	00 00	00 02	03 E8

Response OK: reception of 4 bytes

FC	MEI	Prot	Nid	Index	Sub	Offset	Length
2B	0D	00	1F	20 3C	02	00 00	00 00

Failure: SDO cancellation code

FC	MEC	Ext length	MEI	Excpt code	SDO abort code
AB	FF	00 06	0D	EC	06 02 00 00