YASKAWA MECHATROLINK-II SI-T3 Technical Manual page 16

7 Transmission Interface
Figure 6
Communications Phases
The SI-T3 changes status as described here when a command code or fault is received from the master.
Figure 7
Disconnecting:
DISCONNECT command
Phase 1: Initial status after power ON
Operation proceeds with a default transmission cycle of 2 ms. The transmission cycle is changed to the time indicated in
the synchronous frame when a CONNECT command is received from the master. Then the phase moves to phase 2 or
phase 3 after a response to the CONNECT command is returned.
Even if a transfer fault is detected in phase 1, no fault notification is provided.
Phase 2: Asynchronous communications
All SI-T3 commands can be used. Phase 2 starts to count the watchdog timer in the communications frame. The phase
moves to phase 3 when a SYNC_SET command is received, and it moves to phase 1 when a DISCONNECT command is
received.
16
Command data
+00H +00H
Station address
+01H +01H
Control code
+02H +02H
Command code
−
+03H +03H
+04H +04H
Data
+11H +11H
WDT
+12H +12H
Sub-command
−
+13H +13H
+14H +14H
Data
+1FH +1FH
Not used.
+21H +21H
Figure 7 Basic format of data transfer (32-byte data transmission)
Phase 1 (Initial status)
Connecting:
CONNECT command
(Asynchronous communications)
Phase 2 (Asynchronous communications status)
Set Synchronization
(SYNC_SET command)
Phase 3 (Synchronous communications status)
Figure 8 Communication phases
YASKAWA ELECTRIC SIEP C730600 50A YASKAWA AC Drive-Option Card MECHATROLINK-II Technical Manual
Response data
Station address
Header of data link layer
Control code
Response code
Alarm
Status
Application layer
Data
EWDT
Sub-command
Sub-status
Data in data link layer
Data
Not used.
Power ON
Disconnecting:
DISCONNECT command
Communications fault
Watchdog timer fault
Connecting:
CONNECT command
(Synchronous communications)