Omron C200HW-PRM21 Operation Manuals page 96

Messages
Error message
Extended diagnostics
Master address
Identifier
80
There are two types of responses. The response can either be an answer
message to the issued command or an error message.
The error message occurs due to a syntax error in the command message. In
this case the low byte of word n+2 will be unequal to zero to indicate the error;
the values of the other words should not be considered valid.
Note If bit IR n+2.13,'Reply in input mailbox', does not get set after issuing the
request for slave diagnostics with the IOWR instruction, the command
message in the PLC data area is not correct.
The slave diagnostic bit will only get set when the extended diagnostic data
does not contain all zeros or when the slave is noted as not being existent.
The lower byte of word n+6 contains the exact length in bytes of the message
starting from word n+8. This represents the actual diagnostic data received
from the slave. The maximum data length is 244 (F4h).
The data starting from word n+11 is slave specific, some slaves do not have
extended diagnostic information. The first extended data byte has a fixed
format and describes the type of diagnostics, the rest of the data bytes are
slave specific. The slave manual should give information about the definition
of the extended diagnostics.
The 'Master address' byte contains the address of the master which has
parameterised the DP slave. If no master has parameterised the DP slave,
the value of this byte is FFh.
Word n+10 contains the manufacturer identifier of the DP slave, as registered
at the Profibus Nutzerorganisation (PNO).
Section 6-4