Siemens SIMATIC TI505 User Manual page 52

SIMATIC TI505/TI500 MODNIM User Manual
The diagnostics codes supported are described in the following paragraphs.
Diagnostic Code — 00
0000 | any data
When Function Code 08 uses diagnostic code 0000, any data passed in the
information field is returned to the host computer by the addressed
secondary node without change.
The purpose of this command is to determine if the communications are
functioning correctly, and may be used in conjunction with diagnostic tests
described later.
This code has no effect on the functioning of the MODNIM.
Diagnostic Code — 01
0001 | 00 00
or
0001 | FF 00
When Function Code 08 uses diagnostic code 0001, the information frame
can contain 0000 or FF00.
This function causes the MODNIM to clear all internal counters and
registers. If the MODNIM had been in Listen Only Mode (LOM), it will be
returned to normal operating mode at the successful conclusion of the
command. If the information frame contains FF00, the Communications
Event Log will be cleared. If any other value is passed in the information
field, the Communications Event Log will not be cleared, and no response
will be returned.
This code has significant effect on the functioning of the MODNIM.
Information frame
Diagnostic code
Information frame
Diagnostic code
Modbus Commands 2-21