YASKAWA SI-P3/V Technical Manual page 24

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. Figure 15 describes the handshaking function. The arrow marks indicate whether the PROFIBUS-DP master
or the SI-P3/V unit has the control for the protocol.
Figure 14
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
24
PROFIBUS-DP Master
Handshaking Output Register
0
⇓
0
⇓
1
1
1
⇓
1
⇓
0
0
0
⇓
0
⇓
1
Figure 15 Example of Handshaking
SI-P3/V Unit
Handshaking Input Register
0
0
⇒
0
0
1
1
⇒
1
1
0
0
⇒
0
YASKAWA ELECTRIC SIEP C730600 23B V1000 Option PROFIBUS-DP Technical Manual
Synchronize command bits
to start the message process
New MEMOBUS/Modbus
Command to SI-P3/V Unit
⇓
Command Executed
⇓
Response Valid
New MEMOBUS/Modbus
Command to SI-P3/V Unit
⇓
Command Executed
⇓
Response Valid
New MEMOBUS/Modbus
Command to SI-P3/V Unit
⇓
etc.