Specifications

Advanced Configuration Features
250
EIO0000000051 6/2010
The most significant bit of an RTP request block’s toggle+CMD byte is the toggle
bit. A new command is identified when the value of this bit changes and matches the
value of the toggle bit in the toggle+length byte.
A new RTP request is processed only if the preceding RTP request has finished.
Overlapping RTP requests are not allowed. A new RTP request made before the
completion of a preceding request is ignored.
To determine when an RTP command has been processed and its response is
complete, check the values of the toggle+CMD echo bytes in the RTP response
block. Continue to check both toggle+CMD bytes in the RTP response block until
they match the RTP request block’s toggle+CMD byte. Once they match, the
contents of the RTP response block is valid.
Valid RTP Status Messages
The following list shows valid status messages:
The most significant bit of the status byte in the RTP response block indicates
whether RTP is enabled (1) or disabled (0).
Status Byte Code Comment
Success 0x00 or 0x80 0x00 for successful completion of
a Disable RTP command
Command not Processed due to
Disabled RTP
0x01 -
Illegal CMD 0x82 -
Illegal Data Length 0x83 -
Illegal Node ID 0x84 -
Illegal Node State 0x85 Access is denied because a node
is absent or not started.
Illegal Index 0x86 -
RTP Response Has More Than 4
Bytes
0x87 -
No Communication Possible on the
Island Bus
0x88 -
Illegal Write to Node 127 0x89 -
SDO Aborted 0x90 If an SDO protocol error is
detected, the data bytes in the
response contain the SDO abort
code according to DS301.
General Exception Response 0xFF This is a status event of a type
other than those specified above.