ProSoft Technology ILX69-PBM - Manual (Page 79)

ILX69-PBM ♦ CompactLogix or MicroLogix Platform Contents
PROFIBUS Master Communication Module User Manual
ProSoft Technology, Inc. Page 79 of 124
February 4, 2015
Slave Diagnostics Request Registers
Bytes 4 to 7 contain the Slave Diagnostics Request Register. In combination with the
handshake request bits, these registers are used to provide an easy method to execute a
diagnostics request to a specified PROFIBUS slave.
The Slave Diagnostics Command can be executed by using the corresponding handshake
request bit HsReq0 in the Device Command Register (see section Device Command
Registers (page 77)). The result of the Slave Diagnostics Command can be read in the
Slave Diagnostics field of the input array.
Byte
Offset Data
Type Structure
Member Description
4 SINT SLA Slave Address
5 SINT FNC Function value
6 SINT Reserved Reserved
7 SINT Reserved Reserved
Slave Address
Address of the slave of which the diagnostics data are requested.
Function
If FNC is 0, the diagnostics data is requested from the internal buffer of the ILX69-PBM. This
is the recommended method since the ILX69-PBM always has the most recent slave
diagnostics data in its internal buffer.
If FNC is 1, the diagnostics data is requested directly from the slave itself. This is not the
preferred method because it causes additional bus loading and will influence the bus cycle
time.
Note: The same Slave Diagnostics function can also be executed by CIP
message functionality described later in this manual. The slave diagnostics
can only give the mandatory diagnostics information of a slave. Extended
diagnostics information can be received with the CIP message
functionality.