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F.5 Communications Timing
F.5
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 Bypass
The master must wait for a specified time between receiving a response and resending the same type of command to the same
slave bypass 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 bypass 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 units 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 drive response causes overrun in the master.
412
Table F.4 Minimum Wait Time for Sending Messages
Example
Controller →Bypass
Bypass →Controller
Command message
Response message
Figure F.5 Minimum Wait Time for Sending Messages
Controller
→
Bypass
Bypass
Command message
Response message
24 bit length
Z3-07 setting
Figure F.6 Minimum Response Wait Time
Controller→Bypass
Command message
Master Send
24 bit length
Wait Time
→
Controller
→
Controller
Command message
YASKAWA SIEP YAIZ1D 01C Z1000U HVAC MATRIX Drive Bypass Technical Manual
Table
Minimum Wait Time
<1>
5 ms
H5-11 = 0: 50 ms
<1>
H5-11 = 1: 200 ms
200 ms to 2 s, depending on the number
of parameters that were changed
5 s
Time
Bypass
Time
F.4.
<1>
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