YASKAWA PROFIBUS-DP 1000 Series Technical Manual page 27

Flowchart
Figure 13 illustrates the handshaking function when using a MEMOBUS/Modbus message.
Figure 13
Power ON or
re-initialization
NO
NO
YASKAWA ELECTRIC SIEP C730600 42B 1000-Series Option SI-P3 Technical Manual
PROFIBUS-DP Master
START
Clears the handshaking
register HS bit to "0"
Sends a new message
YES
Creates a command message.
Toggles handshaking
register HS bit <1>
Sends to slave
INDATA HS =
YES
Handles the response
Figure 13 MEMOBUS/Modbus Message Flowchart
SI-P3 Card
START
Initialization
Clears handshaking
register HS bit to "0".
<1> "Toggle" means changing
Receives for the master
Command message
Normal
Command executed
Creates a response message
Toggles handshaking
register HS bit <1>
Sends to master
7 Option Data and I/O Maps
the HS bit status from
0 to 1 or from 1 to 0.
Abnormal
Command not executed
Creates a response
27