YASKAWA SI-P3 Technical Manual page 20

7 Conventional Formats
Example of Handshaking
■
Clear the handshaking register HS bit (bit 7) to 0 for the PLC program after turning on the power supply or after re-initializing.
the handshaking function. The arrow marks indicate whether the PROFIBUS-DP master or the SI-P3 card has the control for the protocol.
Figure 6
Synchronize Command Bits
to Start the Message Process
Create
Command
Signal New
Message Waiting
Create
Command
Signal New
Message Waiting
Create
Command
Signal New
Message Waiting
20
PROFIBUS-DP Master
Handshaking Output Register
0
⇓
0
⇓
1
1
1
⇓
1
⇓
0
0
0
⇓
0
⇓
1
Figure 7 Example of Handshaking
YASKAWA ELECTRIC SIEP C730600 42A YASKAWA AC Drive-Option Card PROFIBUS-DP Technical Manual
SI-P3 Card
Handshaking Input Register
0
0
⇒
0
⇓
0
⇓
1
1
⇒
1
⇓
1
⇓
0
0
⇒
0
⇓
etc.
Figure 7 describes
Synchronize command bits
to start the message process
New MEMOBUS/Modbus
Command to SI-P3 Card
Command Executed
Response Valid
New MEMOBUS/Modbus
Command to SI-P3 Card
Command Executed
Response Valid
New MEMOBUS/Modbus
Command to SI-P3 Card