Communications Timing; Communications Timing; Command Messages From Master To Bypass; Response Messages From Bypass To Master - YASKAWA P1000 Technical Manual

D.6 Communications Timing
To prevent a communications overrun in the slave bypass, the master should wait a certain time between sending messages
to the same bypass. In the same way, the slave bypass 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 Bypass

The master must wait for a specified time between receiving a response and resending the same type of command to the same
bypass drive to prevent overrun and data loss. The minimum wait time depends on the command as shown in
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
4 Enter with storage to drive EEPROM after initialization
<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.
Set a timer in the master to check how long it takes for the slave bypass(es) to respond to the master. If no response is received
within a certain amount of time, the master should try resending the message.
u

Response Messages from Bypass to Master

If the bypass receives a command from the master, it will process the data received and wait for the time set in Z3-07 until it
responds. Increase Z3-07 if the bypass response causes overrun in the master.
YASKAWA SIEP YAIP1B 01B YASKAWA AC Drive – P1000 Bypass Technical Manual
Table D.1 Minimum Wait Time for Sending Messages
Example
PLC→Bypass Bypass→PLC
Command message Response message
Z3-07
24-bit length
setting
Figure D.4 Minimum Response Wait Time
D.6 Communications Timing
Minimum Wait Time
5 ms
200 ms
200 ms to 2 s, depending on the number
of parameters that were changed
PLC→Bypass
Command message
Time
Table D.1.
<1>
<1>
<1>
5 s
D
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