Omron CS1W-PRM21 Operation Manual page 168

Slave Diagnostics Byte 3
A layout of Byte 2 is shown below. This byte is mapped to the high-byte of Word D + 1.
Bit Name
00 Reserved
~
06
07 Diag.Ext_Diag_Overflow
Slave Diagnostics Byte 4
Slave Diagnostics Byte 4 is mapped to the low byte of Word D+1. This byte contains the PROFIBUS address of
the Master Unit, which parameterized the slave. If the slave is not parameterized correctly, the byte contains FF
(Hex) or 255 (Decimal).
Slave Diagnostics Bytes 5 to 6
Slave Diagnostics Bytes 5 and 6 are mapped to Word D+2. They contain the PROFIBUS ID Number of the
slave station. The ID number uniquely identifies the type of device. The ID Number is a 16-bit code issued by
the PROFIBUS Organization. For example, the ID number of the CJ1W-PRT21 PROFIBUS-DP slave is 0602
(Hex).
B-4 Extended Diagnostics Data Bytes
The afore mentioned 6 diagnostics bytes are a mandatory minimum, which is supported by every PROFIBUS-
DP slave device. Depending on the device however, it may also support extended diagnostics information,
which is coded in to the bytes following the first 6 mandatory bytes. The number of extended bytes depends on
the coding and the events that have occurred in the slave device. Normally, they will not be added to the stan-
dard diagnostics message, i.e. the first 6 mandatory bytes, if no event occurred.
There are three types of extended diagnostics information:
• Device related diagnostics
• Module related diagnostics
• Channel related diagnostics
The Module related diagnostics, are usually followed by the Channel related diagnostics. Both the Device
related diagnostics and the Module / Channel related diagnostics can occur in one message.
Device Related Diagnostics
The Device related diagnostics data block consist of a header byte followed by one or more device dependent
diagnostics data bytes. The header byte indicates the type of diagnostics data and the total length of the data
block. The header byte layout is shown below.
154
7 6 5 4 3 2 1 0
Byte 3
These bits are reserved and always set to 0 by the slave station.
If set, this bit indicates that there exists more diagnostic information than speci-
fied in Ext_Diag_Data. This bit will - for example - be set if the slave station has
more diagnostics available than it can enter in its send buffer. This bit will also be
set if the Master Unit receives more diagnostic information than it can enter in its
diagnostic buffer.
Diag.Ext_Diag_Overflow
Description
Appendix