Unidrive M SI-PROFIBUS User Guide 87
Issue Number: 3
Safety
information
Introduction
Mechanical
installation
Electrical
installation
Getting
started
Parameters
GSD
Files
Cyclic data
Non-cyclic
data
Control and
status words
Diagnostics
PROFIdrive
profile (V4)
Advanced
features
Legacy
features
Glossary of
terms
Index
Example response
Data word = 0x9102
Stamp number = 1
TELEGRAM 2
The second telegram from the PROFIBUS-DP master also indicates a READ cycle, but
the stamp number is now 2. The data byte would contain the parameter number for the
parameter that is to be read.
Example telegram
Data word = 0x9201
Stamp number = 2
Parameter = 1
When the second telegram has been received and processed in the slave, it is mirrored
in the non-cyclic IN word. This is the signal to the master controller program that the
second telegram of the message has been received and the third telegram can now be
transmitted.
Example response
Data word = 0x9201
Stamp number = 2
Bit b15-b12 b11-b8 b7-b4 b3-b0
Value 1001 0001 0000 0010
If a telegram produces an error at any point in the sequence the reply to the master will
have the error bit ERR set to a 1.
Bit b15-b12 b11-b8 b7-b4 b3-b0
Value 1001 0010 0000 0001
If telegrams 1 and 2 were not received correctly or an invalid parameter was specified,
(e.g. parameter is write only, or does not exist), the PROFIBUS-DP interface will set the
ERROR bit to 1 (b14 = 1) in the response. The data bits will have no significance.
Setting the stamp number to 0 resets the internal non-cyclic state machine.
Bit b15-b12 b11-b8 b7-b4 b3-b0
Value 1001 0010 0000 0001
If an error is reported, the non-cyclic data word should be set to 0 to ensure that the
non-cyclic state machine is completely reset and ready for the next non-cyclic READ or
WRITE sequence.
To Next Page
Loading...
