Moeller DeviceNet NZM-XDMI612, User Manual, Page: 22 / 50

CANopen Interface
18
05/04 AWB1230-1543GB
Write using expedited transfer
A special case is a write action using expedited transfer. This
procedure can be applied if only one byte has to be
transferred. The telegram is assembled as follows:
Expedited transfer is particularly suitable for sending
commands to the DMI or NZM, or altering individual
parameters.
Read data
Here the procedure is more complicated than for writing. The
following steps must be observed:
1. Request data (segmented transfer),
2. Check that the data are ready for transfer
(expedited transfer),
3. Read out the data (segmented transfer).
Request data
Initiate SDO download
To request data you need the following information:
• the address from where the data are to be read out,
• the number of bytes to be read,
• the statement that this is a read access.
Index: 2021
hex
Subindex: 00
hex
1st data byte: Command code 69
hex
(= write 1 byte)
2nd data
byte: 00
hex
(DMI address, H byte (always 0);
a chapter “Data”, page 23)
3rd data
byte: DMI address, L byte
4th data
byte: Value to be written