Number Of Retries - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

■Number of retries

When a communication failure occurs due to a problem such as noise, change the value so that the number of retries may
increase. The number of retries is obtained using the following formula. (When using the default values, 3 = 30  10)
Number of retries = TCP ULP timer value  TCP resend timer value
Ex.
When the number of retries is three and data sending fails, a data sending error occurs at the timing shown in the figure below
(in communications using the fixed buffer).
BUFSND instruction
BUFSND instruction
Completion device + 1
Data
command
A: TCP resend timer value (The time at which data are sent when ACK is not returned after data transmission)
When not performing the above retry process (when setting 0 time), configure the setting so that the following formula is met.
TCP ULP timer value = TCP end timer value = TCP resend timer value
(Set the same value for the timer values.)
2 PARAMETER SETTINGS
262
2.3 Application Settings
RJ71EN71
1st retry 2nd retry
A A
TCP ULP timeout value
1 scan
3rd retry
A