C.6 Communications Timing - YASKAWA L1000A Technical Manual

C.6 Communications Timing

C.6 Communications Timing
To prevent 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.
◆ Command Messages from Master to Drive
The master must wait for a specified time between receiving a response and re-sending 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
1
2
3
<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.
Figure C.7
A timer should be set in the master to check how long it takes for the slave drive (s) to respond to the master. If no
response is received within a certain amount of time, the master should try resending the message.
◆ 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.
Figure C.8
452
Table C.2 Minimum Wait Time for Sending Messages
• Control command (Run, Stop)
• Set inputs/outputs
• Read monitors and parameter values
Write parameters
Save changes using an Enter command
PLC→Drive
Command message
Figure C.7 Minimum Wait Time for Sending Messages
PLC→Drive
Command message
24 bit length
Figure C.8 Minimum Response Wait Time
Example
Drive→PLC
Response message
Master Send
24 bit length
Wait Time
Drive→PLC
Response message
H5-06
setting
YASKAWA ELECTRIC SIEP C710616 38F YASKAWA AC Drive - L1000A Technical Manual
Minimum Wait Time
H5-11 = 0: 50 ms
H5-11 = 1: 200 ms
200 ms to 2 s, depending on the number of
parameters that were changed
PLC→Drive
Command message
Time
common_
TMonly
PLC→Drive
Command message
Time
common_
TMonly
5 ms
<1>
<1>