Yaskawa APOGEE FLN P1 - Manual (Page 26)

8 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. Similarly, 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 Table 9 .
Table 9 Minimum Wait Time for Sending Messages
Example Minimum Wait Time
• Control command (Run, Stop) Write parameters
• Set inputs/outputs
• Read monitors and parameter values
5 ms
Command message Response message Command message
PLC→Drive PLC→Drive Drive→PLC
24 bit length
Master Send
Wait Time
Time
Figure 12 Minimum Wait Time for Sending Messages
Set a timer in the master to check how long it takes for the slave drive(s) to respond to the
master. The master should try resending the message if no response is received within a certain
amount of time.
8 Communications Timing
26 YASKAWA TOEP YAICOM 13 Metasys N2 & Apogee FLN P1 SI-J3 Installation & Technical Manual