Communications Timing; Command Messages From Master To Drive; Response Messages From Drive To Master - YASKAWA A1000 HHP Programming Manual

B.6 Communications Timing
To prevent a communications overrun in the slave drive, the master should wait a certain time between sending messages to
the same drive. In the same way, the slave drive must wait before sending response messages to prevent an overrun in the
master. This section explains the message timing.
u

Command Messages from Master to Drive

The master must wait for a specified time between receiving a response and resending the same type of command to the same
slave drive to prevent overrun and data loss. The minimum wait time depends on the command as shown in the table below.
Command Type
• Control command (Run, Stop)
1 • Set inputs/outputs
• Read monitors and parameter values
2 • Write parameters
3 • Save changes using an Enter command
<1> If the drive receives command type 1 data during the minimum wait time, it will perform the command and then respond. However, if it receives
a command type 2 or 3 during that time, either a communication error will result or the command will be ignored.
u

Response Messages from Drive to Master

If the drive receives a command from the master, it will process the data received and wait for the time set in H5-06 until it
responds. Increase H5-06 if the drive response causes overrun in the master.
YASKAWA ELECTRIC SIEP YEAHHP 01B YASKAWA AC Drive – A1000 HHP Programming Manual
Table B.2 Minimum Wait Time for Sending Messages
Example
PLC→Drive Drive→PLC
Command message Response message
Figure B.7 Minimum Wait Time for Sending Messages
PLC→Drive Drive→PLC
Command message Response message
H5-06
24 bit length
setting
Figure B.8 Minimum Response Wait Time
PLC→Drive
Command message
Master Send
24 bit length
Wait Time
PLC→Drive
Command message
B.6 Communications Timing
Minimum Wait Time
5 ms
50 ms
<1>
3 to 5 s
Time
Time
B
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